OGS

Line plots across dimensions of each concept
Line plots across concepts
Tables

Plots across concepts

Expenses

Balance Sheet

Assets

Current Assets

NonCurrent Assets

Liabilities

Current Liabilities

Noncurrent Liabilities

Stockholders Equity

Per Share

CashFlow

NetCashProvidedByUsedInOperatingActivities

NetCashProvidedByUsedInInvestingActivities

OperatingLeaseLiability

LesseeOperatingLeaseLiabilityPaymentsDue

AccountsReceivable

Tables

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:CommonStockValue	██████████████████████████████▁	0.535	0.532	0.532	0.531	0.529	0.529	0.528	0.527	0.527	0.527	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.521	0.52	0.52	0.52	0.0
us-gaap:PreferredStockParOrStatedValuePerShare		NA	NA	1e-08	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:SharesIssued us-gaap:StatementEquityComponents us-gaap:CommonStock		NA	NA	53.166733	NA	NA	NA	52.771749	NA	NA	NA	52.598005	NA	NA	NA	52.598005	NA	NA	NA	52.598005	NA	NA	NA	52.598005	NA	NA	NA	52.083859	NA	NA	NA	0.0001
us-gaap:CommonStockSharesIssued	██████████████████████████████▁	53.499237	53.245011	53.166733	53.096893	52.92053	52.860808	52.771749	52.736623	52.734222	52.686634	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.598005	52.590112	52.083859	52.045742	51.992547	51.973052	0.0001
us-gaap:CommonStockSharesAuthorized	██████████████████████████████▁	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	250.0	0.001
us-gaap:CommonStockSharesOutstanding	██████████████████████████████▁	53.499237	53.245011	53.166733	53.096893	52.92053	52.860808	52.771749	52.736623	52.734222	52.686634	52.564902	52.516828	52.516828	52.46988	52.312516	52.273444	52.267296	52.431914	52.28326	52.245273	52.240948	52.161588	52.259224	52.151279	52.102754	52.590112	52.083859	52.045742	51.992547	51.973052	0.0001
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding	█▁	53.548	53.515	NA	53.408	53.264	53.268	NA	53.267	53.215	53.206	NA	53.112	52.899	52.897	NA	52.926	52.969	53.056	NA	52.942	52.836	53.107	NA	53.072	53.438	53.446	NA	53.014	52.446	52.512	NA
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic	█▁	53.466	53.372	NA	53.19	53.053	53.007	NA	52.933	52.89	52.825	NA	52.736	52.692	52.604	NA	52.488	52.553	52.576	NA	52.453	52.386	52.519	NA	52.408	52.767	52.707	NA	52.361	51.797	52.334	NA
us-gaap:EarningsPerShareBasic	▃█▅▂▃█▅▂▃█▄▂▂█▄▂▂▇▄▂▂▆▄▁▂▅▄▁▁▅▃	0.56	1.79	1.1	0.4	0.48	1.73	0.97	0.33	0.46	1.77	0.85	0.31	0.39	1.73	0.9	0.36	0.39	1.45	0.81	0.24	0.39	1.23	0.75	0.14	0.23	1.15	0.7	0.09	0.18	1.13	0.5799999999999998
us-gaap:EarningsPerShareDiluted	▃█▅▂▃█▅▂▃█▄▂▂█▄▂▂▇▄▂▂▆▄▁▂▅▃▁▁▅▃	0.56	1.79	1.0900000000000003	0.39	0.48	1.72	0.96	0.33	0.46	1.76	0.84	0.31	0.39	1.72	0.89	0.36	0.39	1.44	0.8	0.24	0.38	1.22	0.74	0.14	0.23	1.13	0.69	0.09	0.18	1.13	0.5799999999999998

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:ComprehensiveIncomeNetOfTax	▃█▅▂▃█▄▂▃█▄▂▂█▄▂▂▇▄▂▂▆▄▁▂▅▃▁▂▅▃	30.392	95.875	56.623	21.302	25.548	91.901	49.247	17.617	24.63	93.82	45.785	16.479	20.622	90.755	45.955	18.925	20.752	76.585	41.653	12.853	20.415	64.859	39.552	7.512	12.218	60.521	34.982	4.575	12.769	55.683	30.318
us-gaap:CostOfGoodsAndServicesSold	▁█	93.701	314.069	NA	40.485	62.51	226.139	NA	49.607	82.588	365.076	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	▃█▅▂▃█▅▂▃█▄▂▂█▆▂▃█▅▂▃▇▅▁▂▇▄▁▂▇▄	36.557	114.5	69.774	25.335	31.159	111.723	65.115	21.597	30.627	112.262	61.198	21.947	26.846	115.774	78.538	29.883	33.16	114.557	67.036	20.637	32.875	104.789	62.164	12.0	19.65	98.195	59.554	7.315	15.371	95.888	49.906
us-gaap:IncomeTaxExpenseBenefit	▂▄▃▁▂▄▃▁▂▄▄▂▂▅▆▃▃█▅▂▃█▅▁▂█▅▁▂▇▄	6.464	18.925	11.443	4.256	5.834	20.046	13.953	4.14	6.157	18.602	16.494	5.671	6.427	24.939	31.419	11.086	12.537	38.101	24.722	7.9	12.575	40.046	22.962	4.629	7.574	37.814	22.947	2.662	5.917	36.812	19.588
us-gaap:InterestExpense	▇███████▇█▇▄▃▄▃▃▃▃▃▂▂▂▂▃▂▂▁▂▃▅█	14.996	15.44	15.427	15.542	15.843	15.693	15.713	15.783	15.399	15.786	14.585	12.365	12.003	12.352	11.784	11.495	11.305	11.481	11.235	10.809	10.848	10.847	10.978	11.233	11.19	11.169	9.956	11.16	11.776	12.95	15.664
us-gaap:NetIncomeLoss	▃█▅▂▃█▅▂▃█▄▂▂█▄▂▂▇▄▂▂▆▄▁▂▅▃▁▁▅▃	30.093	95.575	58.331	21.079	25.325	91.677	51.162	17.457	24.47	93.66	44.704	16.276	20.419	90.835	47.119	18.797	20.623	76.456	42.315	12.737	20.3	64.743	39.202	7.371	12.076	60.381	36.607	4.653	9.454	59.076	30.318
us-gaap:OperatingIncomeLoss	▃█▅▂▃█▅▂▃█▅▂▂█▅▂▃█▅▂▃▇▄▁▂▇▄▁▁▇▄	51.102	130.345	85.025	40.679	44.608	133.204	81.971	38.777	46.891	127.619	80.855	36.241	41.043	130.29	89.512	40.78	44.052	125.132	78.534	30.892	43.621	116.073	73.903	24.951	31.27	109.005	70.01	19.119	26.812	109.353	65.014
us-gaap:OtherComprehensiveIncomeLossNetOfTax	▅▅▃▅▅▅▃▅▅▅▆▅▅▄▃▅▅▅▄▅▅▅▅▅▅▅▃▄█▁▅	0.299	0.3	-1.708	0.223	0.223	0.224	-1.915	0.16	0.16	0.16	1.081	0.203	0.203	-0.08	-1.164	0.128	0.129	0.129	-0.661	0.116	0.115	0.116	0.35	0.141	0.142	0.14	-1.625	-0.078	3.315	-3.393	0.0
us-gaap:OtherNonoperatingIncomeExpense	▆▆▆▆█▁▅▅▅▆▂▄▄▄▃▃▃▃	0.451	-0.405	0.176	0.198	2.394	-5.788	-1.143	-1.397	-0.865	0.429	-5.072	-1.929	-2.194	-2.164	-3.503	-3.715	-3.9	-3.407	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:RegulatedOperatingRevenue	▂▇▅▁▂▆▅▁▂█▅▁▂█	315.646	625.293	484.173	244.64	273.287	528.168	452.607	248.563	290.56	661.0	464.466	238.28	292.521	638.464	NA	247.142	279.689	550.408	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:Assets	██▆▆▆▆▆▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▅▄▄▅▁	8183.649	8679.904	6028.712	5763.764	5681.612	5674.905	5708.3	5533.18	5446.606	5524.292	5468.642	5152.957	5067.919	5159.093	5206.878	4971.063	4873.13	4889.874	4942.791	4693.679	4610.832	4598.104	4644.41	4506.321	4525.96	4605.488	4649.21	4264.977	4283.81	4382.018	1e-06
us-gaap:LiabilitiesAndStockholdersEquity	▇█▄▄▄▄▄▃▃▃▃▃▃▃▃▃▂▃▃▂▂▂▂▂▂▂▂▂▂▂▁	8183.649	8679.904	6028.712	5763.764	5681.612	5674.905	5708.3	5533.18	5446.606	5524.292	5468.642	5152.957	5067.919	5159.093	5206.878	4971.063	4873.13	4889.874	4942.791	4693.679	4610.832	4598.104	4644.41	4506.321	4525.96	4605.488	4649.21	4264.977	4283.81	4382.018	3846.475
us-gaap:StockholdersEquity	██████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▆▆▇▆▆▆▆▁	2317.266	2296.599	2233.311	2200.017	2191.987	2189.012	2129.39	2101.881	2108.463	2104.78	2042.656	2016.624	2022.344	2020.948	1960.209	1931.992	1933.296	1944.578	1888.28	1862.344	1875.588	1867.187	1841.555	1810.921	1818.893	1839.665	1794.037	1770.996	1780.086	1782.732	1e-06

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:AssetsCurrent	▃█▃▁▁▂▂▁▁▂▃▁▁▂▃▂▂▂▃▁▁▂▂▂▂▃▄▂▃▄▃	603.711	1158.671	539.869	369.704	347.389	407.667	506.202	389.683	376.812	516.27	543.287	374.511	350.709	501.696	588.994	445.553	411.579	481.132	568.923	377.173	381.456	417.611	482.845	417.347	477.519	604.444	667.501	505.182	570.928	724.348	602.184
us-gaap:CashAndCashEquivalentsAtCarryingValue		NA	NA	7.993	NA	NA	NA	17.853	12.562	11.114	19.628	21.323	12.43	12.58	44.536	14.413	6.872	5.113	13.206	14.663	4.513	54.257	52.657	2.433	52.974	135.886	142.502	11.943	59.685	161.326	178.646	1e-06
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	▃█▁▁▁▁▁▁▁▁▁	209.07	704.911	7.993	6.184	10.454	11.069	17.853	12.562	11.114	19.628	21.323	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:ReceivablesNetCurrent	▂▅▅▁▂▄▅▂▃▇▆▂▂▆▆▂▂▄▅▁▁▃▄▁▂▆▆▂▃█▇	160.647	279.591	292.985	106.777	138.885	234.327	260.012	130.768	169.801	338.082	295.421	132.436	163.967	303.493	298.768	127.689	152.278	249.155	290.944	105.06	115.265	195.158	216.343	103.406	142.701	308.85	326.749	135.75	192.104	398.809	356.988
us-gaap:OtherAssetsCurrent	▇▅▅▃▃▂▂▂▂▃▂▁▂▂▂▁▂▂▂▁▂▂▂▁▁▆▇▆▅▅█	45.419	34.757	35.406	24.126	23.311	21.041	20.906	16.992	18.946	21.43	20.495	13.762	18.154	18.754	17.807	15.014	20.014	18.616	19.257	12.457	20.222	16.794	16.789	12.227	13.843	43.903	49.516	40.527	33.892	35.323	54.24

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:OperatingLeaseRightOfUseAsset		NA	NA	37.2	NA	NA	NA	34.2	35.8	37.3	38.5	32.0	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:OtherAssetsNoncurrent	██▇▇▇▇▇▆▆▇▃▄▃▃▃▃▃▃▃▃▄▃▄▄▄▄▄▄▄▄▁	101.922	105.809	96.877	92.158	95.304	93.712	87.883	80.936	86.889	88.637	46.211	49.528	48.003	48.403	47.157	43.625	47.711	46.563	43.773	47.142	49.294	43.247	55.838	54.905	57.728	52.274	51.313	52.79	57.758	54.376	17.658

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:AccountsPayableCurrent	▅█▅▁▁▂▄▁▁▄▆▁▂▂▅▁▁▂▄▂▁▁▃▁▁▃▅▃▃▆▆	158.353	227.955	152.313	65.311	62.71	82.088	120.49	62.575	67.578	119.629	174.51	68.332	70.429	77.566	143.681	68.184	60.458	76.142	131.988	70.562	59.983	59.887	107.482	57.24	67.819	105.058	159.064	97.653	100.357	175.526	169.5
us-gaap:AccruedLiabilitiesCurrent	▄	21.4	NA	36.401	NA	NA	NA	NA	NA	NA	NA	30.294	23.968	20.724	12.835	30.058	18.535	16.202	12.474	22.931	17.812	15.314	15.0	31.47	18.0	14.651	13.648	26.019	20.768	NA	NA	4.791
us-gaap:LiabilitiesCurrent	▃█▇▅▄▇█▆▅▆▆█▇█▆▃▂▂▃▁▁▁▂▁▁▂▃▂▂▃▇	369.305	879.036	797.079	575.714	490.755	776.153	872.737	677.755	578.353	658.191	698.891	836.027	749.338	844.706	673.33	392.228	292.685	307.943	443.933	258.832	217.984	228.593	304.221	233.469	246.936	300.003	392.433	274.148	268.362	363.987	769.077
us-gaap:OperatingLeaseLiabilityCurrent		NA	NA	7.0	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:OtherLiabilitiesCurrent	▃▆▇▇▇██▆▇▇▂▁▁▁▂▂▂▃▁▁▁▃▁▁▂▂▃▂▃▅▄	28.255	57.583	78.952	68.898	72.511	80.675	84.603	66.66	75.098	73.967	18.446	7.858	10.102	10.395	21.465	19.466	23.982	26.884	9.451	8.212	10.965	25.749	11.7	10.478	14.839	18.324	28.132	21.372	34.794	54.155	42.422

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:LongTermDebt	██▁	4099.999999999999	4099.999999999999	1300.0	NA	1600.0	1300.0	1300.0	1300.0	1300.0	1300.0	1300.0	1200.0	1200.0	1200.0	1200.0	NA	1200.0	1200.0	1200.0	1200.0	1200.0	1200.0	1200.0	1200.0	1200.0	NA	1200.0	NA	NA	NA	1000.0
us-gaap:LongTermDebtNoncurrent	██▄▄▄▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▁	4082.83	4082.661	1582.428	1582.193	1581.931	1286.193	1286.064	1285.937	1285.811	1285.587	1285.483	893.88	893.671	893.463	1193.257	1193.052	1192.848	1192.647	1192.446	1192.248	1192.05	1191.854	1201.305	1201.306	1201.308	1201.31	1201.311	1201.313	1201.314	1201.316	1.318
us-gaap:DeferredTaxLiabilitiesNoncurrent		NA	NA	656.806	NA	NA	NA	682.632	675.613	673.939	666.438	652.426	634.65	628.532	625.724	599.945	1089.061	1077.992	1065.096	1038.568	1011.691	987.906	967.943	951.785	907.647	900.63	897.458	894.585	835.345	834.686	831.371	743.452
us-gaap:DeferredIncomeTaxLiabilitiesNet	▅▇▃▁▁█▆	670.672	685.901	656.806	642.309	637.975	698.877	682.632	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	▁▁▁▂▂▂▂▄▄▄▄▃▃▄▄▇████▇▇▇▇▇▇█	82.122	89.86	97.637	98.257	104.075	109.865	115.657	164.206	168.387	173.296	178.72	155.443	160.382	166.611	172.938	282.904	296.881	300.535	303.507	291.23	263.869	268.081	272.309	274.073	277.878	286.654	287.779	NA	NA	NA	0.0
us-gaap:OtherLiabilitiesNoncurrent	▃▃▃▃▄▄▄▄▄▄▂▂▂▂▂▂▂▂▂▂▁▁▁▂▂▂▂▇██▁	102.613	108.718	113.888	110.016	116.774	120.595	118.302	120.827	122.776	124.257	89.6	94.616	91.935	89.539	87.778	81.826	79.428	79.075	76.057	77.334	73.435	74.446	73.235	78.905	80.315	80.398	79.065	183.175	199.362	202.612	65.974
us-gaap:OperatingLeaseLiabilityNoncurrent		NA	NA	30.8	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo		NA	NA	7.4	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree		NA	NA	6.2	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour		NA	NA	4.7	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive		NA	NA	4.1	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive		NA	NA	11.0	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:StockholdersEquity	██████▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇▆▆▇▆▆▆▆▁	2317.266	2296.599	2233.311	2200.017	2191.987	2189.012	2129.39	2101.881	2108.463	2104.78	2042.656	2016.624	2022.344	2020.948	1960.209	1931.992	1933.296	1944.578	1888.28	1862.344	1875.588	1867.187	1841.555	1810.921	1818.893	1839.665	1794.037	1770.996	1780.086	1782.732	1e-06
us-gaap:CommonStockValue	██████████████████████████████▁	0.535	0.532	0.532	0.531	0.529	0.529	0.528	0.527	0.527	0.527	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.521	0.52	0.52	0.52	0.0
us-gaap:AdditionalPaidInCapital	██████████████████████████████▁	1776.911	1755.476	1756.921	1751.35	1735.788	1729.587	1733.092	1728.237	1725.843	1720.22	1727.492	1725.361	1723.795	1721.701	1737.551	1735.638	1734.083	1732.335	1749.574	1748.965	1756.799	1754.899	1764.875	1762.508	1764.17	1759.934	1758.796	1755.539	1754.636	1752.105	0.0
us-gaap:RetainedEarningsAccumulatedDeficit	██▇▇▇▇▆▆▆▆▅▅▅▅▄▄▄▄▃▃▃▃▂▂▂▂▂▁▁▁▁	546.998	548.068	483.635	454.205	461.962	465.411	402.509	377.941	387.077	389.177	320.869	300.547	308.652	312.595	246.121	221.185	224.57	226.195	161.021	137.221	142.996	141.18	95.046	71.746	80.273	84.239	39.894	18.486	28.401	33.5	0.0
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax	▂▁▁▃▂▂▂▄▄▃▄▃▃▃▃▄▄▄▄▄▄▄▄▄▄▃▃▅▅▅█	-7.178	-7.477	-7.777	-6.069	-6.292	-6.515	-6.739	-4.824	-4.984	-5.144	-4.086	-5.167	-5.37	-5.573	-5.493	-4.329	-4.457	-4.586	-4.715	-4.054	-4.17	-4.285	-4.401	-4.751	-4.892	-5.034	-5.174	-3.549	-3.471	-3.393	0.0
us-gaap:StockIssuedDuringPeriodValueNewIssues	█▁	21.178	-1.705	NA	15.336	5.974	-3.736	NA	2.169	5.397	-5.353	4.409	1.961	4.909	-5.879	4.217	1.725	5.017	-6.766	2.569	-7.812	6.243	3.219	6.73	0.161	6.892	0.88	2.634	2.639	2.531	1.811	NA

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:NetCashProvidedByUsedInOperatingActivities	▇▁▇▇▇█▇▇██▇▇██▇▇██▇▇▇█▇▇▇█▇▇▇█▇	81.917	-1659.265	39.171	46.644	95.952	182.733	21.802	47.372	118.88	122.291	30.926	36.811	176.673	223.284	-48.604	23.133	117.035	162.236	0.137	14.117	87.274	180.039	44.669	6.986	101.462	241.09	-3.345	-11.688	79.598	182.098	-21.916
us-gaap:NetCashProvidedByUsedInInvestingActivities	▁▃▁▂▁▂▂▁▃▅▂▃▄▅▃▄▅▆▆▅▇▆▄▆▆█▆▆▅▇▅	-117.941	-101.203	-122.56	-112.794	-121.837	-113.181	-114.115	-121.483	-100.991	-86.343	-115.104	-103.512	-89.235	-86.599	-107.303	-94.251	-83.779	-70.41	-77.735	-86.576	-69.399	-74.869	-94.642	-74.253	-70.511	-54.914	-72.484	-76.002	-82.886	-65.731	-85.425
us-gaap:NetCashProvidedByUsedInFinancingActivities	▁█▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂	-459.817	2457.386	85.198	61.88	25.27	-76.336	97.604	75.559	-26.403	-37.643	93.071	66.551	-119.394	-106.562	163.448	72.877	-41.349	-93.283	87.748	22.715	-16.275	-54.946	-0.568	-15.645	-37.567	-55.617	28.087	-13.951	-14.032	59.108	107.83
us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	▁█	-495.841	696.918	NA	-4.27	-0.615	-6.784	NA	1.448	-8.514	-1.695	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:DeferredIncomeTaxExpenseBenefit	▂▄▂▁▁▂▂▁▂▂▃▂▂▅▆▃▃▇▅▅▄▃█▂▁▃█▁▁▁▄	6.387	18.567	7.31	1.396	2.923	6.856	4.208	-0.302	4.573	4.828	16.605	6.091	6.469	24.077	31.064	11.021	12.847	37.461	27.017	23.74	19.918	16.113	44.405	6.232	2.692	10.46	47.107	0.948	1.728	0.152	19.572
us-gaap:IncreaseDecreaseInAccountsPayable	▁▇▇▄▃▃▆▄▂▂█▄▃▂▇▄▃▂▆▄▄▂▆▃▂▂▆▄▁▄█	-73.683	87.202	79.224	0.072	-16.693	-34.227	54.372	-4.325	-56.168	-53.172	100.742	4.571	-12.019	-56.409	67.928	3.009	-15.035	-53.957	60.519	9.974	-2.837	-40.06	45.313	-12.577	-38.594	-53.777	63.182	-3.671	-72.483	6.091	93.725
us-gaap:IncreaseDecreaseInInventories	▇▃▅▇▆▃▅▆▇▃▄▇▆▂▄▇▆▄▄▇▆▃▄▇▇▁▄██▂▄	41.427	-49.625	-11.431	33.185	24.16	-56.227	-14.191	30.215	36.76	-55.82	-19.186	45.999	29.926	-79.598	-27.487	42.645	23.765	-34.201	-18.798	40.489	23.188	-61.6	-17.759	40.021	38.614	-104.023	-32.02	65.275	70.391	-84.474	-33.968
us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet		NA	NA	-21.68	7.801	11.835	9.748	-13.631	4.609	-4.491	2.824	-12.263	0.991	-1.371	10.69	-3.568	8.035	9.327	-3.447	-45.996	6.147	30.729	-14.999	-9.346	4.187	-5.779	17.085	-25.161	30.892	3.478	6.601	-6.152
us-gaap:NetCashProvidedByUsedInOperatingActivities	▇▁▇▇▇█▇▇██▇▇██▇▇██▇▇▇█▇▇▇█▇▇▇█▇	81.917	-1659.265	39.171	46.644	95.952	182.733	21.802	47.372	118.88	122.291	30.926	36.811	176.673	223.284	-48.604	23.133	117.035	162.236	0.137	14.117	87.274	180.039	44.669	6.986	101.462	241.09	-3.345	-11.688	79.598	182.098	-21.916
us-gaap:NetIncomeLoss	▃█▅▂▃█▅▂▃█▄▂▂█▄▂▂▇▄▂▂▆▄▁▂▅▃▁▁▅▃	30.093	95.575	58.331	21.079	25.325	91.677	51.162	17.457	24.47	93.66	44.704	16.276	20.419	90.835	47.119	18.797	20.623	76.456	42.315	12.737	20.3	64.743	39.202	7.371	12.076	60.381	36.607	4.653	9.454	59.076	30.318
us-gaap:ShareBasedCompensation	▅▄▄▄▅▄▄▄▅▄▄▄▄▄▄▄▄▄▃▃▅▆█▁▃▄▄▄▃▃▁	3.092	2.587	2.364	2.35	2.828	2.261	2.161	2.242	2.957	1.954	2.0	2.115	2.135	1.945	1.946	1.979	2.53	2.421	1.878	1.89	3.35	4.101	5.324	0.179	1.2	2.484	1.962	2.002	1.855	1.794	0.0

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:NetCashProvidedByUsedInInvestingActivities	▁▃▁▂▁▂▂▁▃▅▂▃▄▅▃▄▅▆▆▅▇▆▄▆▆█▆▆▅▇▅	-117.941	-101.203	-122.56	-112.794	-121.837	-113.181	-114.115	-121.483	-100.991	-86.343	-115.104	-103.512	-89.235	-86.599	-107.303	-94.251	-83.779	-70.41	-77.735	-86.576	-69.399	-74.869	-94.642	-74.253	-70.511	-54.914	-72.484	-76.002	-82.886	-65.731	-85.425
us-gaap:PaymentsToAcquirePropertyPlantAndEquipment	█▆█▇█▇▇█▆▄▇▆▅▄▆▅▄▃▃▄▃▃▅▃▃▁▃▃▄▂▄	117.946	99.093	122.43	113.972	121.426	113.517	111.525	121.448	101.046	83.303	115.104	103.512	89.235	86.599	107.304	94.391	84.195	70.471	77.735	86.576	69.499	75.261	94.642	74.253	70.511	54.914	72.484	76.002	82.886	65.731	85.708

		2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:NetCashProvidedByUsedInFinancingActivities	▁█▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂	-459.817	2457.386	85.198	61.88	25.27	-76.336	97.604	75.559	-26.403	-37.643	93.071	66.551	-119.394	-106.562	163.448	72.877	-41.349	-93.283	87.748	22.715	-16.275	-54.946	-0.568	-15.645	-37.567	-55.617	28.087	-13.951	-14.032	59.108	107.83
us-gaap:PaymentsOfDividends	██▇▇▇▇▇▇▇▇▆▆▆▆▆▆▆▆▅▅▅▅▅▅▅▅▄▄▄▁▁	30.903	30.882	28.674	28.608	28.547	28.543	26.369	26.368	26.344	26.343	24.162	24.16	24.135	24.137	21.955	21.954	22.008	22.034	18.286	18.285	18.258	18.38	15.648	15.645	15.76	15.773	14.575	14.568	14.553	0.0	0.0

	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:LongtermDebtType ogs:NotePayableDue2024	NA	NA	NA	3.6099999999999997e-06	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	3.61e-08	NA	NA	NA	NA	NA
us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:LongtermDebtType ogs:NotePayableDue2030MemberDomain	NA	NA	NA	2e-06	2e-08	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:LongtermDebtType ogs:NotePayableDue2048	NA	NA	NA	4.5e-06	4.5e-08	4.5e-08	4.5e-08	4.5e-08	4.5e-08	4.5e-08	4.5e-08	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:LongtermDebtType ogs:NotesPayableDue2044	NA	NA	NA	4.658e-06	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	4.6580000000000004e-08	NA	NA	NA	NA	NA

Common Stock Value

us-gaap:CommonStockValue

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	535000.0	532000.0	532000.0	531000.0	529000.0	529000.0	528000.0	527000.0	527000.0	527000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	521000.0	520000.0	520000.0	520000.0	0
Percentage of CommonStockValue	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Preferred Stock Par Or Stated Value Per Share

us-gaap:PreferredStockParOrStatedValuePerShare

Period End	2020-12-31
Value	0.01
Percentage of PreferredStockParOrStatedValuePerShare	100.0

Shares Issued

us-gaap:SharesIssued us-gaap:StatementEquityComponents

us-gaap:SharesIssued

us-gaap:CommonStock

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	53	52	52	52	52	52	52	0.0001	0.0	0.0
Percentage of SharesIssued	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0

Common Stock Shares Issued

us-gaap:CommonStockSharesIssued

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2014-01-31	2013-12-31
Value	53	53	53	53	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	51	51	51	0.0001
Percentage of CommonStockSharesIssued	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:CommonStockSharesIssued us-gaap:StatementEquityComponents

us-gaap:CommonStock

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	53	53	53	53	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	51	51	0.0001
Percentage of CommonStockSharesIssued	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Common Stock Shares Authorized

us-gaap:CommonStockSharesAuthorized

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2014-01-31	2013-12-31
Value	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	250	0.001
Percentage of CommonStockSharesAuthorized	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Common Stock Shares Outstanding

us-gaap:CommonStockSharesOutstanding

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	53	53	53	53	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	51	51	0.0001
Percentage of CommonStockSharesOutstanding	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31	2016-09-30	2016-06-30	2016-03-31	2015-09-30	2015-06-30	2015-03-31	2014-09-30	2014-06-30	2014-03-31	2013-09-30	2013-06-30	2013-03-31
Value	53	53	53	53	53	53	53	53	53	52	52	52	52	53	52	52	53	53	53	53	53	52	52	52	52	52
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31	2016-09-30	2016-06-30	2016-03-31	2015-09-30	2015-06-30	2015-03-31	2014-09-30	2014-06-30	2014-03-31	2013-09-30	2013-06-30	2013-03-31
Value	53	53	53	53	53	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	52	51	52	52	52	52
Percentage of WeightedAverageNumberOfSharesOutstandingBasic	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	0.56	1.79	1.1	0.4	0.48	1.73	0.97	0.33	0.46	1.77	0.85	0.31	0.39	1.73	0.9	0.36	0.39	1.45	0.81	0.24	0.39	1.23	0.75	0.14	0.23	1.15	0.7	0.09	0.18	1.13	0.58	0.01	0.29	1.02
Percentage of EarningsPerShareBasic	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	0.56	1.79	1.09	0.39	0.48	1.72	0.96	0.33	0.46	1.76	0.84	0.31	0.39	1.72	0.89	0.36	0.39	1.44	0.8	0.24	0.38	1.22	0.74	0.14	0.23	1.13	0.69	0.09	0.18	1.13	0.58	0.01	0.29	1.02
Percentage of EarningsPerShareDiluted	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	30	95	56	21	25	91	49	17	24	93	45	16	20	90	45	18	20	76	41	12	20	64	39	7.512	12	60	34	4.575	12	55	30	0.434	14	53
Percentage of ComprehensiveIncomeNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Cost Of Goods And Services Sold

us-gaap:CostOfGoodsAndServicesSold

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31
Value	93	314	40	62	226	49	82	365
Percentage of CostOfGoodsAndServicesSold	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	36	114	69	25	31	111	65	21	30	112	61	21	26	115	78	29	33	114	67	20	32	104	62	12	19	98	59	7.315	15	95	49	0.309	24	87
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	6.464	18	11	4.256	5.834	20	13	4.14	6.157	18	16	5.671	6.427	24	31	11	12	38	24	7.9	12	40	22	4.629	7.574	37	22	2.662	5.917	36	19	-0.125	9.15	33
Percentage of IncomeTaxExpenseBenefit	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Interest Expense

us-gaap:InterestExpense

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	14	15	15	15	15	15	15	15	15	15	14	12	12	12	11	11	11	11	11	10	10	10	10	11	11	11	9.956	11	11	12	15	15	15	15
Percentage of InterestExpense	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Net Income Loss

us-gaap:NetIncomeLoss

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	30	95	58	21	25	91	51	17	24	93	44	16	20	90	47	18	20	76	42	12	20	64	39	7.371	12	60	36	4.653	9.454	59	30	0.434	14	53
Percentage of NetIncomeLoss	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	30	95	21	25	91	17	24	93	44	16	20	90	47	18	20	76	42	12	20	64	39	7.371	12	60	36	4.653	9.454	33
Percentage of NetIncomeLoss	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	56.7
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Revenues us-gaap:RetainedEarnings	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Operating Income Loss

us-gaap:OperatingIncomeLoss

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	51	130	85	40	44	133	81	38	46	127	80	36	41	130	89	40	44	125	78	30	43	116	73	24	31	109	70	19	26	109	65	14	39	101
Percentage of OperatingIncomeLoss	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	299000.0	300000.0	-1708000.0	223000.0	223000.0	224000.0	-1915000.0	160000.0	160000.0	160000.0	1081000.0	203000.0	203000.0	-80000.0	-1164000.0	128000.0	129000.0	129000.0	-661000.0	116000.0	115000.0	116000.0	350000.0	141000.0	142000.0	140000.0	-1625000.0	-78000.0	3315000.0	-3393000.0	0	0	0	0
Percentage of OtherComprehensiveIncomeLossNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30
Value	299000.0	300000.0	223000.0	223000.0	224000.0	160000.0	160000.0	160000.0	1081000.0	203000.0	203000.0	-80000.0	-1164000.0	128000.0	129000.0	129000.0	-661000.0	116000.0	115000.0	116000.0	350000.0	141000.0	142000.0	140000.0	-1625000.0	-78000.0
Percentage of OtherComprehensiveIncomeLossNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Revenues us-gaap:AccumulatedOtherComprehensiveIncome	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31
Value	451000.0	-405000.0	176000.0	198000.0	2394000.0	-5788000.0	-1143000.0	-1397000.0	-865000.0	429000.0	-5072000.0	-1929000.0	-2194000.0	-2164000.0	-3503000.0	-3715000.0	-3900000.0	-3407000.0
Percentage of OtherNonoperatingIncomeExpense	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:OtherNonoperatingIncomeExpense ogs:OTHERINCOMEANDOTHEREXPENSE

ogs:Netperiodiccostotherthanservicecost

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	-1005000.0	-770000.0	-1310000.0	-1253000.0	-1123000.0	-1364000.0	-1469000.0	-1599000.0	-2336000.0	-2403000.0	-1734000.0	-4313000.0	-4313000.0	-4313000.0
Percentage of OtherNonoperatingIncomeExpense	-222.8	190.1	-661.6	-52.3	19.4	97.6	169.8	-372.7	121.1	109.5	80.1	116.1	110.6	126.6
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Revenues ogs:Netperiodiccostotherthanservicecost	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:Othernet

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	-427000.0	252000.0	-312000.0	-300000.0	-406000.0	-33000.0	604000.0	2028000.0	407000.0	209000.0	-430000.0	598000.0	413000.0	906000.0
Percentage of OtherNonoperatingIncomeExpense	-94.7	-62.2	-157.6	-12.5	7.0	2.4	-69.8	472.7	-21.1	-9.5	19.9	-16.1	-10.6	-26.6
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Revenues ogs:Othernet	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Regulated Operating Revenue

us-gaap:RegulatedOperatingRevenue

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	315	625	484	244	273	528	452	248	290	661	464	238	292	638	247	279	550
Percentage of RegulatedOperatingRevenue	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Assets

us-gaap:Assets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	8183	8679	6028	5763	5681	5674	5708	5533	5446	5524	5468	5152	5067	5159	5206	4971	4873	4889	4942	4693	4610	4598	4644	4506	4525	4605	4649	4264	4283	4382	1e-06
Percentage of Assets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	8183	8679	6028	5763	5681	5674	5708	5533	5446	5524	5468	5152	5067	5159	5206	4971	4873	4889	4942	4693	4610	4598	4644	4506	4525	4605	4649	4264	4283	4382	3846
Percentage of LiabilitiesAndStockholdersEquity	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	384647500000.0

Stockholders Equity

us-gaap:StockholdersEquity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2012-12-31	2011-12-31
Value	2317	2296	2233	2200	2191	2189	2129	2101	2108	2104	2042	2016	2022	2020	1960	1931	1933	1944	1888	1862	1875	1867	1841	1810	1818	1839	1794	1770	1780	1782	1e-06	1154	1158
Percentage of StockholdersEquity	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	28.3	26.5	37.0	38.2	38.6	38.6	37.3	38.0	38.7	38.1	37.4	39.1	39.9	39.2	37.6	38.9	39.7	39.8	38.2	39.7	40.7	40.6	39.7	40.2	40.2	39.9	38.6	41.5	41.6	40.7	100.0	0.0	0.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	-7.178	-7.477	-7.777	-6.069	-6.292	-6.515	-6.739	-4.824	-4.984	-5.144	-4.086	-5.167	-5.37	-5.573	-5.493	-4.329	-4.457	-4.586	-4.715	-4.054	-4.17	-4.285	-4.401	-5.174	0.0	0.0	0.0
Percentage of StockholdersEquity	-0.3	-0.3	-0.3	-0.3	-0.3	-0.3	-0.3	-0.2	-0.2	-0.2	-0.2	-0.3	-0.3	-0.3	-0.3	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.3	0.0	0.0	0.0
Percentage of Assets	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	0.0	0.0	0.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:AdditionalPaidInCapital

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	1776	1755	1756	1751	1735	1729	1733	1728	1725	1720	1727	1725	1723	1721	1737	1735	1734	1732	1749	1748	1756	1754	1764	1758	0.0	0.0	0.0
Percentage of StockholdersEquity	76.7	76.4	78.7	79.6	79.2	79.0	81.4	82.2	81.9	81.7	84.6	85.6	85.2	85.2	88.6	89.8	89.7	89.1	92.7	93.9	93.7	94.0	95.8	98.0	0.0	0.0	0.0
Percentage of Assets	21.7	20.2	29.1	30.4	30.6	30.5	30.4	31.2	31.7	31.1	31.6	33.5	34.0	33.4	33.4	34.9	35.6	35.4	35.4	37.3	38.1	38.2	38.0	37.8	0.0	0.0	0.0
Percentage of Assets us-gaap:AdditionalPaidInCapital	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:CommonStock

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	0.535	0.532	0.532	0.531	0.529	0.529	0.528	0.527	0.527	0.527	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.521	0.0	0.0	0.0
Percentage of StockholdersEquity	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets us-gaap:CommonStock	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:RetainedEarnings

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	546	548	483	454	461	465	402	377	387	389	320	300	308	312	246	221	224	226	161	137	142	141	95	39	0.0	0.0	0.0
Percentage of StockholdersEquity	23.6	23.9	21.7	20.6	21.1	21.3	18.9	18.0	18.4	18.5	15.7	14.9	15.3	15.5	12.6	11.4	11.6	11.6	8.5	7.4	7.6	7.6	5.2	2.2	0.0	0.0	0.0
Percentage of Assets	6.7	6.3	8.0	7.9	8.1	8.2	7.1	6.8	7.1	7.0	5.9	5.8	6.1	6.1	4.7	4.4	4.6	4.6	3.3	2.9	3.1	3.1	2.0	0.9	0.0	0.0	0.0
Percentage of Assets us-gaap:RetainedEarnings	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Assets Current

us-gaap:AssetsCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	603	1158	539	369	347	407	506	389	376	516	543	374	350	501	588	445	411	481	568	377	381	417	482	417	477	604	667	505	570	724	602
Percentage of AssetsCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	7.4	13.3	9.0	6.4	6.1	7.2	8.9	7.0	6.9	9.3	9.9	7.3	6.9	9.7	11.3	9.0	8.4	9.8	11.5	8.0	8.3	9.1	10.4	9.3	10.6	13.1	14.4	11.8	13.3	16.5	60218400000.0

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue

Period End	2020-12-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31	2012-12-31	2011-12-31
Value	7.993	17	12	11	19	21	12	12	44	14	6.872	5.113	13	14	4.513	54	52	2.433	52	135	142	11	59	161	178	1e-06	2.682	3.794	6.412	4.04	4.475
Percentage of CashAndCashEquivalentsAtCarryingValue	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.1	0.3	0.2	0.2	0.4	0.4	0.2	0.2	0.9	0.3	0.1	0.1	0.3	0.3	0.1	1.2	1.1	0.1	1.2	3.0	3.1	0.3	1.4	3.8	4.1	100.0	0.0	0.0	0.0	0.0	0.0

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31
Value	209	704	7.993	6.184	10	11	17	12	11	19	21
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	2.6	8.1	0.1	0.1	0.2	0.2	0.3	0.2	0.2	0.4	0.4

Receivables Net Current

us-gaap:ReceivablesNetCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	160	279	292	106	138	234	260	130	169	338	295	132	163	303	298	127	152	249	290	105	115	195	216	103	142	308	326	135	192	398	356
Percentage of ReceivablesNetCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	2.0	3.2	4.9	1.9	2.4	4.1	4.6	2.4	3.1	6.1	5.4	2.6	3.2	5.9	5.7	2.6	3.1	5.1	5.9	2.2	2.5	4.2	4.7	2.3	3.2	6.7	7.0	3.2	4.5	9.1	35698800000.0

Other Assets Current

us-gaap:OtherAssetsCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	45	34	35	24	23	21	20	16	18	21	20	13	18	18	17	15	20	18	19	12	20	16	16	12	13	43	49	40	33	35	54
Percentage of OtherAssetsCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.6	0.4	0.6	0.4	0.4	0.4	0.4	0.3	0.3	0.4	0.4	0.3	0.4	0.4	0.3	0.3	0.4	0.4	0.4	0.3	0.4	0.4	0.4	0.3	0.3	1.0	1.1	1.0	0.8	0.8	5424000000.0

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset

Period End	2020-12-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31
Value	37	34	35	37	38	32
Percentage of OperatingLeaseRightOfUseAsset	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.6	0.6	0.6	0.7	0.7	0.6

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	101	105	96	92	95	93	87	80	86	88	46	49	48	48	47	43	47	46	43	47	49	43	55	54	57	52	51	52	57	54	17
Percentage of OtherAssetsNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	1.2	1.2	1.6	1.6	1.7	1.7	1.5	1.5	1.6	1.6	0.8	1.0	0.9	0.9	0.9	0.9	1.0	1.0	0.9	1.0	1.1	0.9	1.2	1.2	1.3	1.1	1.1	1.2	1.3	1.2	1765800000.0

Accounts Payable Current

us-gaap:AccountsPayableCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	158	227	152	65	62	82	120	62	67	119	174	68	70	77	143	68	60	76	131	70	59	59	107	57	67	105	159	97	100	175	169
Percentage of AccountsPayableCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	1.9	2.6	2.5	1.1	1.1	1.4	2.1	1.1	1.2	2.2	3.2	1.3	1.4	1.5	2.8	1.4	1.2	1.6	2.7	1.5	1.3	1.3	2.3	1.3	1.5	2.3	3.4	2.3	2.3	4.0	16950000000.0

Accrued Liabilities Current

us-gaap:AccruedLiabilitiesCurrent

Period End	2021-06-30	2020-12-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2013-12-31
Value	21	36	30	23	20	12	30	18	16	12	22	17	15	15	31	18	14	13	26	20	4.791
Percentage of AccruedLiabilitiesCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.3	0.6	0.6	0.5	0.4	0.2	0.6	0.4	0.3	0.3	0.5	0.4	0.3	0.3	0.7	0.4	0.3	0.3	0.6	0.5	479100000.0

Liabilities Current

us-gaap:LiabilitiesCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	369	879	797	575	490	776	872	677	578	658	698	836	749	844	673	392	292	307	443	258	217	228	304	233	246	300	392	274	268	363	769
Percentage of LiabilitiesCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	4.5	10.1	13.2	10.0	8.6	13.7	15.3	12.2	10.6	11.9	12.8	16.2	14.8	16.4	12.9	7.9	6.0	6.3	9.0	5.5	4.7	5.0	6.6	5.2	5.5	6.5	8.4	6.4	6.3	8.3	76907700000.0

Operating Lease Liability Current

us-gaap:OperatingLeaseLiabilityCurrent

Period End	2020-12-31
Value	7000000.0
Percentage of OperatingLeaseLiabilityCurrent	100.0
Percentage of Assets	0.1

Other Liabilities Current

us-gaap:OtherLiabilitiesCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	28	57	78	68	72	80	84	66	75	73	18	7.858	10	10	21	19	23	26	9.451	8.212	10	25	11	10	14	18	28	21	34	54	42
Percentage of OtherLiabilitiesCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.3	0.7	1.3	1.2	1.3	1.4	1.5	1.2	1.4	1.3	0.3	0.2	0.2	0.2	0.4	0.4	0.5	0.5	0.2	0.2	0.2	0.6	0.3	0.2	0.3	0.4	0.6	0.5	0.8	1.2	4242200000.0

Long Term Debt

us-gaap:LongTermDebt

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2014-12-31	2013-12-31
Value	4099	4099	1300	1600	1300	1300	1300	1300	1300	1300	1200	1200	1200	1200	1200	1200	1200	1200	1200	1200	1200	1200	1200	1200	1000
Percentage of LongTermDebt	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	50.1	47.2	21.6	28.2	22.9	22.8	23.5	23.9	23.5	23.8	23.3	23.7	23.3	23.0	24.6	24.5	24.3	25.6	26.0	26.1	25.8	26.6	26.5	25.8	100000000000.0

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	4082	4082	1582	1582	1581	1286	1286	1285	1285	1285	1285	893	893	893	1193	1193	1192	1192	1192	1192	1192	1191	1201	1201	1201	1201	1201	1201	1201	1201	1.318
Percentage of LongTermDebtNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	49.9	47.0	26.2	27.5	27.8	22.7	22.5	23.2	23.6	23.3	23.5	17.3	17.6	17.3	22.9	24.0	24.5	24.4	24.1	25.4	25.9	25.9	25.9	26.7	26.5	26.1	25.8	28.2	28.0	27.4	131800000.0

Deferred Tax Liabilities Noncurrent

us-gaap:DeferredTaxLiabilitiesNoncurrent

Period End	2020-12-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	656	682	675	673	666	652	634	628	625	599	1089	1077	1065	1038	1011	987	967	951	907	900	897	894	835	834	831	743
Percentage of DeferredTaxLiabilitiesNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	10.9	12.0	12.2	12.4	12.1	11.9	12.3	12.4	12.1	11.5	21.9	22.1	21.8	21.0	21.6	21.4	21.1	20.5	20.1	19.9	19.5	19.2	19.6	19.5	19.0	74345200000.0

Deferred Income Tax Liabilities Net

us-gaap:DeferredIncomeTaxLiabilitiesNet

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31
Value	670	685	656	642	637	698	682
Percentage of DeferredIncomeTaxLiabilitiesNet	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	8.2	7.9	10.9	11.1	11.2	12.3	12.0

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2013-12-31
Value	82	89	97	98	104	109	115	164	168	173	178	155	160	166	172	282	296	300	303	291	263	268	272	274	277	286	287	0.0
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	1.0	1.0	1.6	1.7	1.8	1.9	2.0	3.0	3.1	3.1	3.3	3.0	3.2	3.2	3.3	5.7	6.1	6.1	6.1	6.2	5.7	5.8	5.9	6.1	6.1	6.2	6.2	0.0

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	8.635	23	43	64
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	8.8	20.2	24.2	37.5
Percentage of Assets	0.1	0.4	0.8	1.2
Percentage of Assets us-gaap:OtherPostretirementBenefitPlansDefinedBenefit	0.0	0.0	0.0	0.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	89	92	135	108
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	91.2	79.8	75.8	62.5
Percentage of Assets	1.5	1.6	2.5	2.1
Percentage of Assets us-gaap:PensionPlansDefinedBenefit	0.0	0.0	0.0	0.0

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	102	108	113	110	116	120	118	120	122	124	89	94	91	89	87	81	79	79	76	77	73	74	73	78	80	80	79	183	199	202	65
Percentage of OtherLiabilitiesNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	1.3	1.3	1.9	1.9	2.1	2.1	2.1	2.2	2.3	2.2	1.6	1.8	1.8	1.7	1.7	1.6	1.6	1.6	1.5	1.6	1.6	1.6	1.6	1.8	1.8	1.7	1.7	4.3	4.7	4.6	6597400000.0

Operating Lease Liability Noncurrent

us-gaap:OperatingLeaseLiabilityNoncurrent

Period End	2020-12-31
Value	30
Percentage of OperatingLeaseLiabilityNoncurrent	100.0
Percentage of Assets	0.5

Lessee Operating Lease Liability Payments Due Year Two

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearTwo

Period End	2020-12-31
Value	7400000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	100.0
Percentage of Assets	0.1

Lessee Operating Lease Liability Payments Due Year Three

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearThree

Period End	2020-12-31
Value	6200000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearThree	100.0
Percentage of Assets	0.1

Lessee Operating Lease Liability Payments Due Year Four

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFour

Period End	2020-12-31
Value	4700000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFour	100.0
Percentage of Assets	0.1

Lessee Operating Lease Liability Payments Due Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueYearFive

Period End	2020-12-31
Value	4100000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueYearFive	100.0
Percentage of Assets	0.1

Lessee Operating Lease Liability Payments Due After Year Five

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive

Period End	2020-12-31
Value	11
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	100.0
Percentage of Assets	0.2

Operating Lease Liability

us-gaap:OperatingLeaseLiability

Period End	2020-12-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31
Value	37	34	35	37	38	32
Percentage of OperatingLeaseLiability	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.6	0.6	0.6	0.7	0.7	0.6

Lessee Operating Lease Liability Payments Due

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDue

Period End	2020-12-31
Value	41
Percentage of LesseeOperatingLeaseLiabilityPaymentsDue	100.0
Percentage of Assets	0.7

Lessee Operating Lease Liability Undiscounted Excess Amount

us-gaap:LesseeOperatingLeaseLiabilityUndiscountedExcessAmount

Period End	2020-12-31
Value	3500000.0
Percentage of LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	100.0
Percentage of Assets	0.1

Stockholders Equity

us-gaap:StockholdersEquity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2012-12-31	2011-12-31
Value	2317	2296	2233	2200	2191	2189	2129	2101	2108	2104	2042	2016	2022	2020	1960	1931	1933	1944	1888	1862	1875	1867	1841	1810	1818	1839	1794	1770	1780	1782	1e-06	1154	1158
Percentage of StockholdersEquity	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	28.3	26.5	37.0	38.2	38.6	38.6	37.3	38.0	38.7	38.1	37.4	39.1	39.9	39.2	37.6	38.9	39.7	39.8	38.2	39.7	40.7	40.6	39.7	40.2	40.2	39.9	38.6	41.5	41.6	40.7	100.0	0.0	0.0

us-gaap:StockholdersEquity us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	-7.178	-7.477	-7.777	-6.069	-6.292	-6.515	-6.739	-4.824	-4.984	-5.144	-4.086	-5.167	-5.37	-5.573	-5.493	-4.329	-4.457	-4.586	-4.715	-4.054	-4.17	-4.285	-4.401	-5.174	0.0	0.0	0.0
Percentage of StockholdersEquity	-0.3	-0.3	-0.3	-0.3	-0.3	-0.3	-0.3	-0.2	-0.2	-0.2	-0.2	-0.3	-0.3	-0.3	-0.3	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.2	-0.3	0.0	0.0	0.0
Percentage of Assets	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	0.0	0.0	0.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:AdditionalPaidInCapital

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	1776	1755	1756	1751	1735	1729	1733	1728	1725	1720	1727	1725	1723	1721	1737	1735	1734	1732	1749	1748	1756	1754	1764	1758	0.0	0.0	0.0
Percentage of StockholdersEquity	76.7	76.4	78.7	79.6	79.2	79.0	81.4	82.2	81.9	81.7	84.6	85.6	85.2	85.2	88.6	89.8	89.7	89.1	92.7	93.9	93.7	94.0	95.8	98.0	0.0	0.0	0.0
Percentage of Assets	21.7	20.2	29.1	30.4	30.6	30.5	30.4	31.2	31.7	31.1	31.6	33.5	34.0	33.4	33.4	34.9	35.6	35.4	35.4	37.3	38.1	38.2	38.0	37.8	0.0	0.0	0.0
Percentage of Assets us-gaap:AdditionalPaidInCapital	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:CommonStock

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	0.535	0.532	0.532	0.531	0.529	0.529	0.528	0.527	0.527	0.527	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.526	0.521	0.0	0.0	0.0
Percentage of StockholdersEquity	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets us-gaap:CommonStock	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:RetainedEarnings

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2014-12-31	2013-12-31	2012-12-31	2011-12-31
Value	546	548	483	454	461	465	402	377	387	389	320	300	308	312	246	221	224	226	161	137	142	141	95	39	0.0	0.0	0.0
Percentage of StockholdersEquity	23.6	23.9	21.7	20.6	21.1	21.3	18.9	18.0	18.4	18.5	15.7	14.9	15.3	15.5	12.6	11.4	11.6	11.6	8.5	7.4	7.6	7.6	5.2	2.2	0.0	0.0	0.0
Percentage of Assets	6.7	6.3	8.0	7.9	8.1	8.2	7.1	6.8	7.1	7.0	5.9	5.8	6.1	6.1	4.7	4.4	4.6	4.6	3.3	2.9	3.1	3.1	2.0	0.9	0.0	0.0	0.0
Percentage of Assets us-gaap:RetainedEarnings	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Common Stock Value

us-gaap:CommonStockValue

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	535000.0	532000.0	532000.0	531000.0	529000.0	529000.0	528000.0	527000.0	527000.0	527000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	526000.0	521000.0	520000.0	520000.0	520000.0	0
Percentage of CommonStockValue	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Additional Paid In Capital

us-gaap:AdditionalPaidInCapital

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1776	1755	1756	1751	1735	1729	1733	1728	1725	1720	1727	1725	1723	1721	1737	1735	1734	1732	1749	1748	1756	1754	1764	1762	1764	1759	1758	1755	1754	1752	0.0
Percentage of AdditionalPaidInCapital	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	21.7	20.2	29.1	30.4	30.6	30.5	30.4	31.2	31.7	31.1	31.6	33.5	34.0	33.4	33.4	34.9	35.6	35.4	35.4	37.3	38.1	38.2	38.0	39.1	39.0	38.2	37.8	41.2	41.0	40.0	0.0

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	546	548	483	454	461	465	402	377	387	389	320	300	308	312	246	221	224	226	161	137	142	141	95	71	80	84	39	18	28	33	0.0
Percentage of RetainedEarningsAccumulatedDeficit	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	6.7	6.3	8.0	7.9	8.1	8.2	7.1	6.8	7.1	7.0	5.9	5.8	6.1	6.1	4.7	4.4	4.6	4.6	3.3	2.9	3.1	3.1	2.0	1.6	1.8	1.8	0.9	0.4	0.7	0.8	0.0

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	-7.178	-7.477	-7.777	-6.069	-6.292	-6.515	-6.739	-4.824	-4.984	-5.144	-4.086	-5.167	-5.37	-5.573	-5.493	-4.329	-4.457	-4.586	-4.715	-4.054	-4.17	-4.285	-4.401	-4.751	-4.892	-5.034	-5.174	-3.549	-3.471	-3.393	0.0
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0
Percentage of Assets	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	-0.1	0.0

Stock Issued During Period Value New Issues

us-gaap:StockIssuedDuringPeriodValueNewIssues

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	21	-1.705	15	5.974	-3.736	2.169	5.397	-5.353	4.409	1.961	4.909	-5.879	4.217	1.725	5.017	-6.766	2.569	-7.812	6.243	3.219	6.73	0.161	6.892	0.88	2.634	2.639	2.531	1.811
Percentage of StockIssuedDuringPeriodValueNewIssues	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:StockIssuedDuringPeriodValueNewIssues us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	21	-1.705	15	5.974	-3.737	2.169	5.397	-7.499	1.911	1.345	1.867	-16.074	1.685	1.327	1.508	-17.469	0.381	-8.061	1.673	-10.205	2.113	-1.915	3.954	0.875	2.633	2.639	2.531	1.811
Percentage of StockIssuedDuringPeriodValueNewIssues	100.0	100.0	100.0	100.0	100.0	100.0	100.0	140.1	43.3	68.6	38.0	273.4	40.0	76.9	30.1	258.2	14.8	103.2	26.8	-317.0	31.4	-1189.4	57.4	99.4	100.0	100.0	100.0	100.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets us-gaap:AdditionalPaidInCapital	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:CommonStock

Period End	2021-06-30	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	0.003	0.002	0.0	0.001	0.0	0.0	0.001	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.005	0.001	0.0	0.0	0.0
Percentage of StockIssuedDuringPeriodValueNewIssues	0.0	0.0	0.0	-0.0	0.0	0.0	-0.0	0.0	0.0	0.0	-0.0	0.0	0.0	0.0	-0.0	0.0	-0.0	0.0	0.0	0.0	0.0	0.0	0.6	0.0	0.0	0.0	0.0
Percentage of Assets	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Assets us-gaap:CommonStock	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	81	-1659.265	39	46	95	182	21	47	118	122	30	36	176	223	-48.604	23	117	162	0.137	14	87	180	44	6.986	101	241	-3.345	-11.688	79	182	-21.916	-48.885	67	157
Percentage of NetCashProvidedByUsedInOperatingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-117940000.0	-101200000.0	-122560000.0	-112790000.0	-121840000.0	-113180000.0	-114120000.0	-121480000.0	-100990000.0	-86343000.0	-115100000.0	-103510000.0	-89235000.0	-86599000.0	-107300000.0	-94251000.0	-83779000.0	-70410000.0	-77735000.0	-86576000.0	-69399000.0	-74869000.0	-94642000.0	-74253000.0	-70511000.0	-54914000.0	-72484000.0	-76002000.0	-82886000.0	-65731000.0	-85425000.0	-78383000.0	-66812000.0	-60133000.0
Percentage of NetCashProvidedByUsedInInvestingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-459.817	2457	85	61	25	-76.336	97	75	-26.403	-37.643	93	66	-119.394	-106.562	163	72	-41.349	-93.283	87	22	-16.275	-54.946	-0.568	-15.645	-37.567	-55.617	28	-13.951	-14.032	59	107	126	-3.12	-95.19
Percentage of NetCashProvidedByUsedInFinancingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31
Value	-495.841	696	-4.27	-0.615	-6.784	1.448	-8.514	-1.695
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Deferred Income Tax Expense Benefit

us-gaap:DeferredIncomeTaxExpenseBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	6.387	18	7.31	1.396	2.923	6.856	4.208	-0.302	4.573	4.828	16	6.091	6.469	24	31	11	12	37	27	23	19	16	44	6.232	2.692	10	47	0.948	1.728	0.152	19	-0.142	9.117	33
Percentage of DeferredIncomeTaxExpenseBenefit	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Increase Decrease In Accounts Payable

us-gaap:IncreaseDecreaseInAccountsPayable

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-73.683	87	79	0.072	-16.693	-34.227	54	-4.325	-56.168	-53.172	100	4.571	-12.019	-56.409	67	3.009	-15.035	-53.957	60	9.974	-2.837	-40.06	45	-12.577	-38.594	-53.777	63	-3.671	-72.483	6.091	93	-13.205	-27.958	-15.321
Percentage of IncreaseDecreaseInAccountsPayable	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Increase Decrease In Inventories

us-gaap:IncreaseDecreaseInInventories

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	41	-49.625	-11.431	33	24	-56.227	-14.191	30	36	-55.82	-19.186	45	29	-79.598	-27.487	42	23	-34.201	-18.798	40	23	-61.6	-17.759	40	38	-104.023	-32.02	65	70	-84.474	-33.968	95	74	-72.859
Percentage of IncreaseDecreaseInInventories	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Increase Decrease In Other Operating Capital Net

us-gaap:IncreaseDecreaseInOtherOperatingCapitalNet

Period End	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-21.68	7.801	11	9.748	-13.631	4.609	-4.491	2.824	-12.263	0.991	-1.371	10	-3.568	8.035	9.327	-3.447	-45.996	6.147	30	-14.999	-9.346	4.187	-5.779	17	-25.161	30	3.478	6.601	-6.152	-9.866	34	-17.756
Percentage of IncreaseDecreaseInOtherOperatingCapitalNet	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	81	-1659.265	39	46	95	182	21	47	118	122	30	36	176	223	-48.604	23	117	162	0.137	14	87	180	44	6.986	101	241	-3.345	-11.688	79	182	-21.916	-48.885	67	157
Percentage of NetCashProvidedByUsedInOperatingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Net Income Loss

us-gaap:NetIncomeLoss

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	30	95	58	21	25	91	51	17	24	93	44	16	20	90	47	18	20	76	42	12	20	64	39	7.371	12	60	36	4.653	9.454	59	30	0.434	14	53
Percentage of NetIncomeLoss	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	30	95	21	25	91	17	24	93	44	16	20	90	47	18	20	76	42	12	20	64	39	7.371	12	60	36	4.653	9.454	33
Percentage of NetIncomeLoss	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	56.7
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of Revenues us-gaap:RetainedEarnings	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Share Based Compensation

us-gaap:ShareBasedCompensation

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	3.092	2.587	2.364	2.35	2.828	2.261	2.161	2.242	2.957	1.954	2.0	2.115	2.135	1.945	1.946	1.979	2.53	2.421	1.878	1.89	3.35	4.101	5.324	0.179	1.2	2.484	1.962	2.002	1.855	1.794	0.0	0.0	0.0	0.0
Percentage of ShareBasedCompensation	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-117940000.0	-101200000.0	-122560000.0	-112790000.0	-121840000.0	-113180000.0	-114120000.0	-121480000.0	-100990000.0	-86343000.0	-115100000.0	-103510000.0	-89235000.0	-86599000.0	-107300000.0	-94251000.0	-83779000.0	-70410000.0	-77735000.0	-86576000.0	-69399000.0	-74869000.0	-94642000.0	-74253000.0	-70511000.0	-54914000.0	-72484000.0	-76002000.0	-82886000.0	-65731000.0	-85425000.0	-78383000.0	-66812000.0	-60133000.0
Percentage of NetCashProvidedByUsedInInvestingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Payments To Acquire Property Plant And Equipment

us-gaap:PaymentsToAcquirePropertyPlantAndEquipment

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	117	99	122	113	121	113	111	121	101	83	115	103	89	86	107	94	84	70	77	86	69	75	94	74	70	54	72	76	82	65	85	76	67	62
Percentage of PaymentsToAcquirePropertyPlantAndEquipment	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-459.817	2457	85	61	25	-76.336	97	75	-26.403	-37.643	93	66	-119.394	-106.562	163	72	-41.349	-93.283	87	22	-16.275	-54.946	-0.568	-15.645	-37.567	-55.617	28	-13.951	-14.032	59	107	126	-3.12	-95.19
Percentage of NetCashProvidedByUsedInFinancingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of Revenues	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Payments Of Dividends

us-gaap:PaymentsOfDividends

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30
Value	30	30	28	28	28	28	26	26	26	26	24	24	24	24	21	21	22	22	18	18	18	18	15	15	15	15	14	14	14	0.0	0.0	0.0
Percentage of PaymentsOfDividends	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0

Debt Instrument Interest Rate Stated Percentage

us-gaap:DebtInstrumentInterestRateStatedPercentage us-gaap:LongtermDebtType

us-gaap:DebtInstrumentInterestRateStatedPercentage

ogs:NotePayableDue2024

Period End	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-01-31
Value	3.61	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361	0.0361
Percentage of DebtInstrumentInterestRateStatedPercentage	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0
Percentage of LongTermDebtAndCapitalLeaseObligations	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of LongTermDebtAndCapitalLeaseObligations ogs:NotePayableDue2024	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:NotePayableDue2030MemberDomain

Period End	2020-09-30	2020-06-30
Value	2.0	0.02
Percentage of DebtInstrumentInterestRateStatedPercentage	55.4	55.4
Percentage of LongTermDebtAndCapitalLeaseObligations	0.0	0.0
Percentage of LongTermDebtAndCapitalLeaseObligations ogs:NotePayableDue2030MemberDomain	0.0	0.0

ogs:NotePayableDue2048

Period End	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31
Value	4.5	0.045	0.045	0.045	0.045	0.045	0.045	0.045
Percentage of DebtInstrumentInterestRateStatedPercentage	124.7	124.7	124.7	124.7	124.7	124.7	124.7	124.7
Percentage of LongTermDebtAndCapitalLeaseObligations	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of LongTermDebtAndCapitalLeaseObligations ogs:NotePayableDue2048	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:NotesPayableDue2044

Period End	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-01-31
Value	4.658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658	0.04658
Percentage of DebtInstrumentInterestRateStatedPercentage	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0	129.0
Percentage of LongTermDebtAndCapitalLeaseObligations	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of LongTermDebtAndCapitalLeaseObligations ogs:NotesPayableDue2044	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Deferred Tax Liabilities

us-gaap:DeferredTaxLiabilities

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	656	682	652	599	1038	951	887	709
Percentage of DeferredTaxLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:ApproximateAggregateNaturalGasPurchaseCosts

Period End	2021-02-26
Value	2200
Percentage of ApproximateAggregateNaturalGasPurchaseCosts	100.0

ogs:CommonStockDividendsDeclaredAnnualizedBasis us-gaap:SubsequentEventType

ogs:CommonStockDividendsDeclaredAnnualizedBasis

us-gaap:SubsequentEvent

Period End	2021-09-30	2021-06-30	2021-03-31	2020-12-31	2020-03-31	2019-03-31	2018-03-31	2017-03-31
Value	2.32	2.32	2.32	2.16	2.16	2.0	1.84	1.68
Percentage of CommonStockDividendsDeclaredAnnualizedBasis	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:EarningsonInvestmentsAssociatedwithNonqualifiedEmployeeBenefitPlans ogs:OTHERINCOMEANDOTHEREXPENSE

ogs:EarningsonInvestmentsAssociatedwithNonqualifiedEmployeeBenefitPlans

ogs:Earningslossesoninvestmentsassociatedwithnonqualifiedemployeebenefitplans

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31
Value	1883000.0	616000.0	1820000.0	3947000.0	-4259000.0	189000.0	1050000.0	2441000.0
Percentage of EarningsonInvestmentsAssociatedwithNonqualifiedEmployeeBenefitPlans	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:EnvironmentalReserveEstimateRangeHigh

Period End	2020-12-31	2018-06-30
Value	17	7.0
Percentage of EnvironmentalReserveEstimateRangeHigh	100.0	100.0

ogs:EnvironmentalReserveEstimateRangeLow

Period End	2020-12-31	2018-06-30
Value	7100000.0	5600000.0
Percentage of EnvironmentalReserveEstimateRangeLow	100.0	100.0

ogs:IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesCurrent

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	-6.887	20	-15.639	-3.92
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesCurrent	100.0	100.0	100.0	100.0

ogs:IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesNonCurrent

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	-3877.858	1946	24	-8.852
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesNonCurrent	100.0	100.0	100.0	100.0

ogs:OthercomprehensiveincomelossreclassificationRegulatoryadjustments

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	-11.014	-11.013	72	-10.296	-10.296	-10.296	57	-8.44	-8.44	-7.222	66	-9.537	-9.537	9.537	9.288	9.29	9.289	9.29	10	8.943	8.94	8.941	8.728	11	11	11	7.475	8.366	2.848	13
Percentage of OthercomprehensiveincomelossreclassificationRegulatoryadjustments	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Othercomprehensiveincomelossreclassificationadjustmentbeforetaxandregulatoryadjustments

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	11	11	-74.157	10	10	10	-60.569	8.653	8.653	8.653	-68.657	9.808	9.808	-9.808	-9.497	-9.499	-9.499	-9.499	-10.208	-9.131	-9.128	-9.129	-8.958	-12.19	-12.192	-12.192	-8.242	-8.239	-8.238	-8.239
Percentage of Othercomprehensiveincomelossreclassificationadjustmentbeforetaxandregulatoryadjustments	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Otherrevenuesnaturalgassalesrelated ogs:REVENUE

ogs:Otherrevenuesnaturalgassalesrelated

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30
Value	1.325	-1.021	1.821	-0.066	-0.003	6.547	-2.697	0.735	0.207	-2.944	-3.103	0.375	-1.108	1.03	0.57	3.377
Percentage of Otherrevenuesnaturalgassalesrelated	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:ReductioninincometaxexpensefortheamortizationoftheregulatoryliabilityassociatedwithexcessADITthatwasreturnedtocustomers

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31	2019-06-30	2019-03-31
Value	2.6	8.1	2.5	6.9	2.1	6.7
Percentage of ReductioninincometaxexpensefortheamortizationoftheregulatoryliabilityassociatedwithexcessADITthatwasreturnedtocustomers	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:AmortizationOfRateDeferral

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	1.0	2.9	0.6	1.5
Percentage of AmortizationOfRateDeferral	100.0	100.0	100.0	100.0

us-gaap:CapitalExpendituresIncurredButNotYetPaid

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31
Value	-4.1	11	2.7	4.2	-0.7	0.7	1.7	6.7	-4.9	9.7
Percentage of CapitalExpendituresIncurredButNotYetPaid	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:CommonStockDividendsPerShareCashPaid

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30
Value	0.58	0.58	0.54	0.54	0.54	0.54	0.5	0.5	0.5	0.5	0.46	0.46	0.46	0.46	0.42	0.42	0.42	0.42	0.35	0.35	0.35	0.35	0.3	0.3	0.3	0.3	0.28	0.28	0.28	0	0	0	0
Percentage of CommonStockDividendsPerShareCashPaid	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0

us-gaap:CommonStockDividendsPerShareDeclared

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	0.58	0.58	0.54	0.54
Percentage of CommonStockDividendsPerShareDeclared	100.0	100.0	100.0	100.0

us-gaap:CommonStockDividendsPerShareDeclared us-gaap:SubsequentEventType

us-gaap:SubsequentEvent

Period End	2021-09-30	2021-06-30	2021-03-31	2020-12-31
Value	0.58	0.58	0.58	0.54
Percentage of CommonStockDividendsPerShareDeclared	0.0	100.0	100.0	0.0

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	11	11	-74.361	10	10	10	-61.746	8.821	8.821	8.821	-76.65	10	10	-10.95	-10.647	-10.648	-10.648	-10.648	-10.799	-10.04	-10.036	-10.037	-9.8	-12.564	-12.565	-12.565	-8.544	-8.542	-8.541	-8.542
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAmortizationOfGainsLosses us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	-0.093	-0.093	-0.044	-0.043	-0.043	-0.043	-0.561	-0.561	-0.561	-0.561	-0.971	-0.972	-0.972	-0.972	-1.621	-1.621	-1.621
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses	-0.8	-0.8	0.1	-0.4	-0.4	-0.4	0.9	-6.4	-6.4	-6.4	1.3	-8.9	-8.9	8.9	15.2	15.2	15.2

us-gaap:PensionPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	-11.381	-11.381	-10.579	-10.58	-10.58	-10.58	-8.259	-8.26	-8.26	-8.26	-9.979	-9.978	-9.978	-9.978	-9.026	-9.027	-9.027
Percentage of DefinedBenefitPlanAmortizationOfGainsLosses	-99.2	-99.2	14.2	-99.6	-99.6	-99.6	13.4	-93.6	-93.6	-93.6	13.0	-91.1	-91.1	91.1	84.8	84.8	84.8

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	70000.0	70000.0	-204000.0	29000.0	29000.0	29000.0	-1177000.0	168000.0	168000.0	168000.0	-7993000.0	1142000.0	1142000.0	-1142000.0	-1150000.0	-1149000.0	-1149000.0	-1149000.0	-591000.0	-909000.0	-908000.0	-908000.0	-842000.0	-374000.0	-373000.0	-373000.0	-302000.0	-303000.0	-303000.0	-303000.0
Percentage of DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAmortizationOfPriorServiceCostCredit us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	-70000.0	-70000.0	-30000.0	-29000.0	-29000.0	-29000.0	-169000.0	-168000.0	-168000.0	-168000.0	-1141000.0	-1142000.0	-1142000.0	-1142000.0	-1150000.0	-1149000.0	-1149000.0
Percentage of DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	-100.0	-100.0	14.7	-100.0	-100.0	-100.0	14.4	-100.0	-100.0	-100.0	14.3	-100.0	-100.0	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedReturnOnPlanAssets

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	4.202	4.202	3.868	3.867	3.867	3.867	3.145	3.147	3.147	3.147	3.571	3.571	3.571	3.571	3.149	3.147	3.147
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	15	15	15	15	15	15	15	15	15	15	15	15	15	15	14	14	14
Percentage of DefinedBenefitPlanExpectedReturnOnPlanAssets	371.2	371.2	395.0	395.1	395.1	395.1	492.3	492.1	492.1	492.1	424.1	424.1	424.1	424.1	464.4	464.7	464.7

us-gaap:DefinedBenefitPlanInterestCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanInterestCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	1.563	1.563	1.89	1.889	1.889	1.889	2.331	2.329	2.329	2.329	2.28	2.279	2.279	2.279	2.474	2.472	2.472
Percentage of DefinedBenefitPlanInterestCost	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	7.365	7.365	8.544	8.545	8.545	8.545	10	10	10	10	9.201	9.2	9.2	9.2	10	10	10
Percentage of DefinedBenefitPlanInterestCost	471.2	471.2	452.1	452.4	452.4	452.4	436.1	436.6	436.6	436.6	403.6	403.7	403.7	403.7	408.8	409.1	409.1

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	-2.219	-2.219	-1.541	-1.541	-1.541	-1.541	0.01	0.009	0.009	0.009	-0.874	-0.873	-0.873	-0.873	0.424	0.424	0.424
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	6.603	6.603	7.062	7.062	7.062	7.062	5.947	5.951	5.951	5.951	7.265	7.263	7.263	7.263	7.56	7.56	7.56
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost	-297.6	-297.6	-458.3	-458.3	-458.3	-458.3	59470.0	66122.2	66122.2	66122.2	-831.2	-832.0	-832.0	-832.0	1783.0	1783.0	1783.0

us-gaap:DefinedBenefitPlanServiceCost us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanServiceCost

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	0.397	0.397	0.423	0.423	0.423	0.423	0.432	0.434	0.434	0.434	0.587	0.589	0.589	0.589	0.628	0.627	0.627
Percentage of DefinedBenefitPlanServiceCost	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30
Value	3.453	3.453	3.218	3.217	3.217	3.217	3.006	3.008	3.008	3.008	3.229	3.23	3.23	3.23	3.044	3.044	3.044
Percentage of DefinedBenefitPlanServiceCost	869.8	869.8	760.8	760.5	760.5	760.5	695.8	693.1	693.1	693.1	550.1	548.4	548.4	548.4	484.7	485.5	485.5

us-gaap:DividendsCommonStock

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30
Value	30	30	28	28	28	26	26	26	24	24	24	24	21	21	22	22	18	18	18	18	15	15	15	15	14	14
Percentage of DividendsCommonStock	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DividendsCommonStock us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30
Value	-0.26	-0.26	-0.228	-0.227	-0.232	-0.225	-0.226	-0.227	-0.22	-0.221	-0.227	-0.224	-0.228	-0.228	-0.24	-0.23	-0.228	-0.227	-0.227	-0.229	-0.254	-1.343	0.282	0.263	-0.624	0.0
Percentage of DividendsCommonStock	-0.8	-0.8	-0.8	-0.8	-0.8	-0.9	-0.9	-0.9	-0.9	-0.9	-0.9	-0.9	-1.0	-1.0	-1.1	-1.0	-1.2	-1.2	-1.2	-1.2	-1.6	-8.6	1.8	1.7	-4.3	0.0

us-gaap:RetainedEarnings

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30
Value	31	31	28	28	28	26	26	26	24	24	24	24	22	22	22	22	18	18	18	18	15	15	16	16	15	14
Percentage of DividendsCommonStock	100.8	100.8	100.8	100.8	100.8	100.9	100.9	100.9	100.9	100.9	100.9	100.9	101.0	101.0	101.1	101.0	101.2	101.2	101.2	101.2	101.6	101.6	101.8	101.7	104.3	100.0

us-gaap:EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate

Period End	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31
Value	20.79	0	0.21	0	0	0	0.21	0	0	0	0.21
Percentage of EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	100.0	0.0	100.0	0.0	0.0	0.0	100.0	0.0	0.0	0.0	100.0

us-gaap:ExcessTaxBenefitFromShareBasedCompensationFinancingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31
Value	-36000.0	-4292000.0	-89000.0	-38000.0	-152000.0	-5988000.0	-107000.0	-73000.0	-95000.0	-7300000.0	-4000.0	-289000.0	-42000.0	-7817000.0	-61000.0	-169000.0	-106000.0	-9180000.0	-17000.0	-103000.0	-53000.0	-8849000.0
Percentage of ExcessTaxBenefitFromShareBasedCompensationFinancingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInCustomerDeposits

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-0.476	-10.787	12	-1.63	-1.323	0.285	0.456	-1.3	-3.57	1.218	-0.386	0.32	-0.612	1.05	1.168	-0.88	-1.422	0.736	0.784	-1.013	-0.985	2.098	1.994	-0.848	-1.677	0.853	2.686	0.251	-1.718	1.424	1.503	-0.255	-2.244	0.269
Percentage of IncreaseDecreaseInCustomerDeposits	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInMaterialsAndSupplies

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30
Value	0.928	-1.619	-2.726	0.906	1.196	-2.342	-1.056	6.444	3.449	2.562	3.97	4.239	1.062	-4.61	0.883	1.913	2.588	0.204	3.986	-2.52	2.91	-3.617	-0.075	1.718	5.12	-0.949	-4.63	-3.863
Percentage of IncreaseDecreaseInMaterialsAndSupplies	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInOtherCurrentAssetsAndLiabilitiesNet

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	16303000.0	-20698000.0	-3275000.0	-4575000.0
Percentage of IncreaseDecreaseInOtherCurrentAssetsAndLiabilitiesNet	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet

Period End	2021-06-30	2021-03-31	2020-06-30	2020-03-31
Value	-33.861	14	-11.533	5.173
Percentage of IncreaseDecreaseInOtherNoncurrentAssetsAndLiabilitiesNet	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInOtherRegulatoryAssets

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31
Value	11	9.885	9.951	9.18	9.888	13	13	11
Percentage of IncreaseDecreaseInOtherRegulatoryAssets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInPropertyAndOtherTaxesPayable

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-9.769	2.059	6.068	15	-4.852	-1.182	0.751	9.893	-14.591	4.263	-1.12	13	-12.54	6.147	-3.334	11	-3.869	-5.14	2.652	8.243	-6.108	0.535	-3.18	6.23	-13.66	3.117	1.256	4.845	-17.91	24	-6.452	8.968	-0.997	0.93
Percentage of IncreaseDecreaseInPropertyAndOtherTaxesPayable	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInReceivables

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-117.202	-9.64	202	-30.835	-90.956	-22.608	133	-37.99	-166.987	44	164	-28.844	-138.177	7.447	173	-23.582	-95.657	-39.508	187	-9.441	-78.52	-19.801	114	-38.443	-164.946	-17.003	193	-55.046	-203.885	42	233	-46.245	-145.111	59
Percentage of IncreaseDecreaseInReceivables	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:IncreaseDecreaseInRegulatoryAssetsAndLiabilities

Period End	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	20	8.714	-4.932	-8.007	5.752	3.142	-29.09	-9.169	5.699	-22.243	-83.724	-17.802	8.334	-1.141	-18.641	30	15	2.373	0.593	13	-5.377	4.443	-63.434	-6.759	-4.695	-7.547	-11.066	-1.181	19	-21.522	-26.35
Percentage of IncreaseDecreaseInRegulatoryAssetsAndLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-299000.0	-300000.0	1708000.0	-223000.0	-223000.0	-224000.0	1915000.0	-160000.0	-160000.0	-160000.0	-1081000.0	-203000.0	-203000.0	80000.0	1164000.0	-128000.0	-129000.0	-129000.0	661000.0	-116000.0	-115000.0	-116000.0	-350000.0	-141000.0	-142000.0	-140000.0	1625000.0	78000.0	-3315000.0	3393000.0	0	0	0	0
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	-91000.0	-91000.0	513000.0	-75000.0	-75000.0	-74000.0	638000.0	-53000.0	53000.0	-53000.0	905000.0	-68000.0	-68000.0	-351000.0	728000.0	-81000.0	-81000.0	-80000.0	414000.0	-72000.0	-73000.0	-72000.0	-219000.0	-88000.0	-88000.0	-88000.0	1146000.0	49000.0	-2075000.0	2124000.0	0	0	0	0
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	390000.0	391000.0	-2086000.0	298000.0	298000.0	298000.0	-1491000.0	213000.0	213000.0	213000.0	-1895000.0	271000.0	271000.0	-271000.0	-209000.0	-209000.0	-210000.0	-209000.0	-187000.0	-188000.0	-188000.0	-188000.0	-230000.0	-229000.0	-230000.0	-228000.0	-767000.0	127000.0	-5390000.0	5517000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansBeforeTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	299000.0	300000.0	-1564000.0	223000.0	223000.0	224000.0	-1119000.0	160000.0	160000.0	160000.0	-1137000.0	203000.0	203000.0	80000.0	-129000.0	-128000.0	-129000.0	-129000.0	-115000.0	-116000.0	-115000.0	-116000.0	-141000.0	-141000.0	-142000.0	-140000.0	-471000.0	78000.0	-3315000.0	3393000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	-91000.0	-91000.0	-74000.0	-75000.0	-75000.0	-74000.0	-54000.0	-53000.0	-53000.0	-53000.0	216000.0	-68000.0	-68000.0	-351000.0	-80000.0	-81000.0	-81000.0	-80000.0	-72000.0	-72000.0	-73000.0	-72000.0	-89000.0	-88000.0	-88000.0	-88000.0	-296000.0	49000.0	-2075000.0	2124000.0
Percentage of OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansTax	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PaymentsForProceedsFromOtherInvestingActivities

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-09-30	2016-06-30	2016-03-31	2015-09-30	2015-06-30	2015-03-31
Value	470000.0	2351000.0	564000.0	501000.0	314000.0	-4056000.0	473000.0	543000.0	3040000.0	0	0	0	0	-1000.0	-140000.0	-416000.0	-61000.0	0	-100000.0	-392000.0	0	0	0
Percentage of PaymentsForProceedsFromOtherInvestingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0	100.0	100.0	100.0	100.0	0.0	100.0	100.0	0.0	0.0	0.0

us-gaap:PaymentsOfDebtIssuanceCosts

Period End	2021-06-30	2021-03-31	2020-09-30
Value	0.0	35	0.0
Percentage of PaymentsOfDebtIssuanceCosts	0.0	100.0	0.0

us-gaap:ProceedsFromIssuanceOfCommonStock

Period End	2020-12-31	2020-09-30	2019-12-31	2019-09-30	2018-12-31	2018-09-30	2017-12-31	2017-09-30	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	3.058	13	2.58	0.0	2.413	0.0	2.249	0.0	2.034	0.0	1.983	0.0	2.58	0.0	2.315	2.156	0.671	0.637	0.676	0.017	0.0	0.0	0.0	0.0
Percentage of ProceedsFromIssuanceOfCommonStock	100.0	100.0	100.0	0.0	100.0	0.0	100.0	0.0	100.0	0.0	100.0	0.0	100.0	0.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0

us-gaap:ProceedsFromIssuanceOfSeniorLongTermDebt

Period End	2021-06-30	2021-03-31	2020-09-30
Value	0.0	2498	0.0
Percentage of ProceedsFromIssuanceOfSeniorLongTermDebt	0.0	100.0	0.0

us-gaap:ProceedsFromRepaymentsOfCommercialPaper

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31
Value	-447.0	28	110	77	-244.195	-41.805	121	102	-2.5	-4.0	23	91	-97.607	-74.608	183	95	-6.4	-59.6	104	41	0.0	-12.5	12	0.0	0.0	-42.0	42	0.0	0.0	0.0
Percentage of ProceedsFromRepaymentsOfCommercialPaper	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	100.0	100.0	0.0	0.0	100.0	100.0	0.0	0.0	0.0

us-gaap:ProceedsFromSaleOfOtherAssetsInvestingActivities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30
Value	475000.0	241000.0	1295000.0	1742000.0	90000.0	650000.0	363000.0	438000.0	287000.0	311000.0	0	0
Percentage of ProceedsFromSaleOfOtherAssetsInvestingActivities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0

us-gaap:ProvisionForDoubtfulAccounts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	1.742	3.754	6.614	1.273	4.486	3.077	4.394	1.043	1.294	2.263	1.748	2.687	1.349	2.722	2.815	1.007	1.22	2.281	1.906	0.764	1.373	1.384	1.569	0.852	1.203	0.896	2.176	1.308	2.82	0.891	1.331	1.463	2.048	0.618
Percentage of ProvisionForDoubtfulAccounts	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatedOperatingRevenueGas

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	311	623	479	240	270	518	452	244	287	661	464	235	291	635	462	247	279	550	440	232	245	508	389	225	256	676	514	241	296	766	522	219	311	635
Percentage of RegulatedOperatingRevenueGas	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatedOperatingRevenueGas ogs:REVENUE

ogs:Miscellaneousrevenues

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	4.073	3.655	4.115	3.8	3.12	4.47	5.046	4.677	5.428	5.428	4.29	4.893	5.759	6.768	4.76	5.196	5.785
Percentage of RegulatedOperatingRevenueGas	1.3	0.6	0.9	1.6	1.2	0.9	1.1	1.9	1.9	0.8	0.9	2.1	2.0	1.1	1.9	1.9	1.1

ogs:Naturalgassalestocustomers

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	281	583	444	212	243	480	416	215	258	621	430	208	261	594	218	247	500
Percentage of RegulatedOperatingRevenueGas	90.3	93.6	92.6	88.3	89.8	92.6	92.1	88.4	89.8	93.9	92.6	88.6	89.8	93.7	88.2	88.5	90.9

ogs:Transportationrevenues

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	26	36	31	24	24	33	31	23	23	35	30	21	24	33	21	21	30
Percentage of RegulatedOperatingRevenueGas	8.4	5.8	6.5	10.1	9.0	6.5	6.9	9.7	8.3	5.3	6.5	9.3	8.3	5.3	8.7	7.6	5.5

us-gaap:RegulatedOperatingRevenueOther

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	3.907	1.642	-3.945	3.812	2.378	9.223	4.134	4.183	2.581	2.816	2.523	1.353	3.227	2.74	5.656	14
Percentage of RegulatedOperatingRevenueOther	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatedOperatingRevenueOther ogs:REVENUE

ogs:Otherrevenues

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31
Value	2.582	2.663	10	3.878	2.381	2.676	-2.567	3.448	2.374	1.996	0.307	2.148	2.461	2.197	2.17	2.279	2.085
Percentage of RegulatedOperatingRevenueOther	66.1	162.2	-274.6	101.7	100.1	29.0	-62.1	82.4	92.0	0.0	10.9	85.1	181.9	68.1	79.2	40.3	14.6

us-gaap:StockIssuedDuringPeriodSharesNewIssues us-gaap:StatementEquityComponents

us-gaap:StockIssuedDuringPeriodSharesNewIssues

us-gaap:CommonStock

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31
Value	254230.0	78278.0	176360.0	59722.0	89059.0	2401.0	47588.0	88629.0	0	0	0
Percentage of StockIssuedDuringPeriodSharesNewIssues	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0

us-gaap:UtilitiesOperatingExpense

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	170	180	190	163	166	168	179	160	161	168	164	150	157	157	162	147	153	162	164	149	145	156	157	145	145	153	154	147	149	150	158	145	139	149
Percentage of UtilitiesOperatingExpense	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:UtilitiesOperatingExpenseDepreciationAndAmortization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	50	52	51	47	47	47	46	45	44	43	41	40	39	38	38	38	37	37	37	36	35	34	34	33	33	31	31	31	31	31	44	32	32	34
Percentage of UtilitiesOperatingExpenseDepreciationAndAmortization	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:UtilitiesOperatingExpenseMaintenanceAndOperations

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	103	110	122	100	103	104	118	100	101	108	109	96	102	102	110	95	101	109	114	99	97	106	109	98	99	106	111	101	103	103	100	99	93	99
Percentage of UtilitiesOperatingExpenseMaintenanceAndOperations	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:UtilitiesOperatingExpenseTaxes

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31	2013-09-30	2013-06-30	2013-03-31
Value	16	17	16	15	15	16	14	14	14	16	14	13	14	16	13	13	13	15	13	13	13	15	13	12	13	15	10	14	14	15	13	13	12	15
Percentage of UtilitiesOperatingExpenseTaxes	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:WeightedAverageNumberDilutedSharesOutstandingAdjustment

Period End	2021-06-30	2021-03-31	2020-09-30	2020-06-30	2020-03-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30	2017-06-30	2017-03-31	2016-09-30	2016-06-30	2016-03-31	2015-09-30	2015-06-30	2015-03-31	2014-09-30	2014-06-30	2014-03-31	2013-09-30	2013-06-30	2013-03-31
Value	82000.0	143000.0	218000.0	211000.0	261000.0	334000.0	325000.0	381000.0	376000.0	207000.0	293000.0	438000.0	416000.0	480000.0	489000.0	450000.0	588000.0	664000.0	671000.0	739000.0	653000.0	649000.0	178000.0	0	0	0
Percentage of WeightedAverageNumberDilutedSharesOutstandingAdjustment	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0

dei:EntityCommonStockSharesOutstanding

Period End	2021-02-22
Value	53
Percentage of EntityCommonStockSharesOutstanding	100.0

ogs:AtTheMarketEquityProgramIssuanceCosts

Period End	2021-06-30	2020-06-30
Value	15	0.4
Percentage of AtTheMarketEquityProgramIssuanceCosts	100.0	100.0

ogs:AttheMarketEquityProgramEquityAvailableforIssuance

Period End	2021-06-30	2021-03-31	2020-06-30
Value	221	236	249
Percentage of AttheMarketEquityProgramEquityAvailableforIssuance	100.0	100.0	100.0

ogs:Capitalizednonservicecostcomponentsasaregulatoryasset

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31
Value	6100000.0	6200000.0	6000000.0	5900000.0	5400000.0	4700000.0	3800000.0	2900000.0	2200000.0	1500000.0
Percentage of Capitalizednonservicecostcomponentsasaregulatoryasset	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Commercialpapermaximumborrowingcapacity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-09-30	2018-06-30	2018-03-31	2017-09-30
Value	1000	700	700	700	700	700	700	700	700	700	700	700	700	700
Percentage of Commercialpapermaximumborrowingcapacity	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Corporatebondsinotherassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31
Value	3800000.0	3600000.0	1600000.0	2900000.0	2300000.0	2600000.0
Percentage of Corporatebondsinotherassets	100.0	100.0	100.0	100.0	100.0	100.0

ogs:DebtInstrumentCovenantComplianceDefaultProvisionIndebtnednessThreshold

Period End	2020-12-31
Value	100
Percentage of DebtInstrumentCovenantComplianceDefaultProvisionIndebtnednessThreshold	100.0

ogs:DeferredTaxAssetsLeasingArrangements

Period End	2020-12-31	2019-12-31	2018-12-31
Value	9319000.0	8599000.0	0
Percentage of DeferredTaxAssetsLeasingArrangements	100.0	100.0	0.0

ogs:Deferredtaxassetemployeebenefitsandotheraccruedliabilities

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	28	32	48	40	123	110	128	0.0
Percentage of Deferredtaxassetemployeebenefitsandotheraccruedliabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0

ogs:Deferredtaxassetregulatoryadjustments

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	121	124	129	129	0.0
Percentage of Deferredtaxassetregulatoryadjustments	100.0	100.0	100.0	100.0	0.0

ogs:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossBeforeRegulatoryAssetsAndTaxes us-gaap:RetirementPlanType

ogs:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossBeforeRegulatoryAssetsAndTaxes

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-13049000.0	-19458000.0	-33269000.0	-43588000.0
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossBeforeRegulatoryAssetsAndTaxes	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-351060000.0	-381630000.0	-419240000.0	-378600000.0
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeLossBeforeRegulatoryAssetsAndTaxes	2690.3	1961.3	1260.1	868.6

ogs:Fairvaluenaturalgascalloptions us-gaap:FairValueByFairValueHierarchyLevel

ogs:Fairvaluenaturalgascalloptions

us-gaap:FairValueInputsLevel1

Period End	2021-06-30	2020-12-31	2020-09-30	2020-06-30	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2017-12-31	2017-09-30	2017-06-30	2016-12-31	2016-09-30	2016-06-30	2015-12-31	2015-09-30	2015-06-30	2014-12-31	2014-09-30	2014-06-30	2013-12-31
Value	11	0.8	15	4.9	0.3	6.0	3.0	2.1	8.6	3.8	1.1	6.9	4.0	6.5	8.1	6.4	0.4	4.4	5.5	0.1	9.5	4.8	8.7
Percentage of Fairvaluenaturalgascalloptions	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Fairvalueofnaturalgascalloptionsheld us-gaap:FairValueByFairValueHierarchyLevel

ogs:Fairvalueofnaturalgascalloptionsheld

us-gaap:FairValueInputsLevel1

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2014-03-31	2013-12-31
Value	800000.0	300000.0	2100000.0	1100000.0	6500000.0	400000.0	100000.0	0	8700000.0
Percentage of Fairvalueofnaturalgascalloptionsheld	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	100.0

ogs:February2021NaturalGasPurchases

Period End	2021-02-28
Value	2100
Percentage of February2021NaturalGasPurchases	100.0

ogs:KGSDeferredExtraordinaryCostsFrom2021WinterStormUri

Period End	2021-06-30	2021-03-31
Value	383	381
Percentage of KGSDeferredExtraordinaryCostsFrom2021WinterStormUri	100.0	100.0

ogs:LineofCreditFacilityOptiontoIncreaseBorrowingCapacity us-gaap:LongtermDebtType

ogs:LineofCreditFacilityOptiontoIncreaseBorrowingCapacity

us-gaap:LineOfCredit

Period End	2020-12-31
Value	500
Percentage of LineofCreditFacilityOptiontoIncreaseBorrowingCapacity	100.0

ogs:LineofCreditFacilitySublimit us-gaap:LongtermDebtType

ogs:LineofCreditFacilitySublimit

us-gaap:LineOfCredit

Period End	2020-12-31
Value	20
Percentage of LineofCreditFacilitySublimit	100.0

ogs:Netregulatoryassetsandliabilitiescurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	27	20	41	51	21	6.159	2.239	5.339	-8.162	-16.031	6.026	7.374	-8.465	4.999	78	88	67	60	71	60	34	22	8.31	-9.634	-15.994	-31.93	17	18	13	14	3.861
Percentage of Netregulatoryassetsandliabilitiescurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Netregulatoryassetsandliabilitiesnoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1771	1809	-180.607	-191.141	-184.874	-113.524	-112.482	-90.821	-84.573	-82.225	-83.387	-146.658	-136.153	-123.381	-114.232	411	421	430	440	424	404	414	426	428	438	450	463	294	304	311	2.447
Percentage of Netregulatoryassetsandliabilitiesnoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:ONEGas2021TermLoanFacilityMaximumBorrowingCapacity us-gaap:LongtermDebtType

ogs:ONEGas2021TermLoanFacilityMaximumBorrowingCapacity

ogs:ONEGas2021TermLoanFacility

Period End	2021-02-22
Value	2500
Percentage of ONEGas2021TermLoanFacilityMaximumBorrowingCapacity	100.0

ogs:Premiumsrecordedinothercurrentassetsonnaturalgascontractsheld

Period End	2021-06-30	2020-12-31	2020-09-30	2020-06-30	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2017-12-31	2017-09-30	2017-06-30	2016-12-31	2016-09-30	2016-06-30	2015-12-31	2015-09-30	2015-06-30	2014-12-31	2014-09-30	2014-06-30	2013-12-31
Value	6.1	6.7	13	5.8	4.4	9.0	3.9	4.1	7.6	3.6	5.5	10	5.6	5.4	9.4	4.1	5.8	11	5.9	6.4	13	6.9	8.6
Percentage of Premiumsrecordedinothercurrentassetsonnaturalgascontractsheld	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:ReclassificationOther

Period End	2020-12-31
Value	10000000.0
Percentage of ReclassificationOther	100.0

ogs:ReductionInADITRecordedAsAnEDITRegulatoryLiabilityAssociatedWithReductionOfOklahomaStateIncomeTax

Period End	2021-06-30
Value	29
Percentage of ReductionInADITRecordedAsAnEDITRegulatoryLiabilityAssociatedWithReductionOfOklahomaStateIncomeTax	100.0

ogs:ReductionToBaseRatesDueToKansasGasServiceTaxReformRegulatoryLiability

Period End	2020-12-31
Value	4900000.0
Percentage of ReductionToBaseRatesDueToKansasGasServiceTaxReformRegulatoryLiability	100.0

ogs:RegulatoryAssetForCostsAssociatedWithManufacturedGasSites

Period End	2021-06-30	2021-03-31	2020-12-31	2019-12-31
Value	18	18	18	9.8
Percentage of RegulatoryAssetForCostsAssociatedWithManufacturedGasSites	100.0	100.0	100.0	100.0

ogs:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFairValueOfSharesGranted us-gaap:AwardType

ogs:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFairValueOfSharesGranted

us-gaap:PerformanceShares

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	6502000.0	6401000.0	5882000.0	5110000.0	4766000.0	4486000.0	4462000.0	2926000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFairValueOfSharesGranted	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RestrictedStockUnitsRSU

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	3005000.0	3001000.0	2583000.0	2420000.0	2503000.0	3141000.0	3149000.0	1323000.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFairValueOfSharesGranted	46.2	46.9	43.9	47.4	52.5	70.0	70.6	45.2

ogs:TGSDeferredExtraordinaryCostsFrom2021WinterStormUri

Period End	2021-06-30	2021-03-31
Value	286	295
Percentage of TGSDeferredExtraordinaryCostsFrom2021WinterStormUri	100.0	100.0

ogs:TotalDeferredCreditsAndOtherLiabilities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1414	1421	1415	1405	1416	1423	1420	1467	1473	1475	1441	1406	1402	1399	1380	1453	1454	1444	1418	1380	1325	1310	1297	1260	1258	1264	1261	1018	1034	1033	809
Percentage of TotalDeferredCreditsAndOtherLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Totalgoodwillandotherassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2590	2610	621	614	626	632	636	655	669	676	641	582	591	601	610	613	626	634	642	636	617	622	649	653	668	675	687	522	538	545	199
Percentage of Totalgoodwillandotherassets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Treasurynotesinotherassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31
Value	3000000.0	3200000.0	3200000.0	2900000.0	3000000.0	3000000.0
Percentage of Treasurynotesinotherassets	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:AccrualForEnvironmentalLossContingencies

Period End	2021-06-30	2021-03-31	2020-12-31	2019-12-31
Value	13	13	14	5.8
Percentage of AccrualForEnvironmentalLossContingencies	100.0	100.0	100.0	100.0

us-gaap:AccrualForTaxesOtherThanIncomeTaxesCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	56	65	63	57	41	46	47	47	37	51	47	48	34	47	41	44	33	37	42	39	31	37	37	40	34	47	44	43	38	56	32
Percentage of AccrualForTaxesOtherThanIncomeTaxesCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax us-gaap:RetirementPlanType

us-gaap:AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-7777000.0	-6739000.0	-4086000.0	-5493000.0
Percentage of AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax	100.0	100.0	100.0	100.0

us-gaap:AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2019-12-31
Value	20	19	16	12	6.6
Percentage of AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	100.0	100.0	100.0	100.0	100.0

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	16	6.6	4.7	4.8	4.2	3.5	4.0	3.3
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:BridgeLoan us-gaap:LongtermDebtType

us-gaap:BridgeLoan

us-gaap:LineOfCredit

Period End	2020-12-31
Value	60
Percentage of BridgeLoan	100.0

us-gaap:CapitalizationLongtermDebtAndEquity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	6400	6379	3815	3782	3773	3475	3415	3387	3394	3390	3328	2910	2916	2914	3153	3125	3126	3137	3080	3054	3067	3059	3042	3012	3020	3040	2995	2972	2981	2984	2267
Percentage of CapitalizationLongtermDebtAndEquity	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:CommercialPaper

Period End	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2013-12-31
Value	447	418	308	230	474	516	395	293	295	299	276	185	282	357	174	79	85	145	41	0.0	0.0	12	0.0	0.0	0.0	42	0.0
Percentage of CommercialPaper	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	100.0	0.0	0.0	0.0	100.0	0.0

us-gaap:CustomerDepositsCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	56	57	68	55	56	58	57	57	58	62	61	61	61	61	60	59	60	61	61	60	61	62	60	58	59	60	60	57	57	58	57
Percentage of CustomerDepositsCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2016-12-31
Value	12	12	13	13	13	10	10	11	11	11	11	7.614	7.614	7.824	8.033	8.239	8.445	8.851
Percentage of DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredIncomeTaxLiabilities

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	820	851	832	797	1190	1069	1030	757
Percentage of DeferredIncomeTaxLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxAssetsGross

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	163	168	180	197	152	117	142	48
Percentage of DeferredTaxAssetsGross	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxAssetsOther

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	4790000.0	2772000.0	34000.0	2984000.0	5716000.0	7848000.0	5655000.0	8249000.0
Percentage of DeferredTaxAssetsOther	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxLiabilitiesLeasingArrangements

Period End	2020-12-31	2019-12-31	2018-12-31
Value	9788000.0	8599000.0	0
Percentage of DeferredTaxLiabilitiesLeasingArrangements	100.0	100.0	0.0

us-gaap:DeferredTaxLiabilitiesOther

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	88	96	105	106	186	168	193	2.563
Percentage of DeferredTaxLiabilitiesOther	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxLiabilitiesPropertyPlantAndEquipment

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	717	742	717	677	990	897	820	750
Percentage of DeferredTaxLiabilitiesPropertyPlantAndEquipment	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxLiabilitiesRegulatoryAssets us-gaap:RetirementPlanType

us-gaap:DeferredTaxLiabilitiesRegulatoryAssets

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	2157000.0	1869000.0	2607000.0	3455000.0
Percentage of DeferredTaxLiabilitiesRegulatoryAssets	100.0	100.0	100.0	100.0

us-gaap:DeferredTaxLiabilitiesRegulatoryAssetsAndLiabilities

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	5.24	3.556	8.981	13	13	3.999	16	4.695
Percentage of DeferredTaxLiabilitiesRegulatoryAssetsAndLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedBenefitObligation

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	1000	937	890	936
Percentage of DefinedBenefitPlanAccumulatedBenefitObligation	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-9934000.0	-8608000.0	-6693000.0	-8948000.0
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-13134000.0	-19660000.0	-34144000.0	-49030000.0
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-351060000.0	-381630000.0	-419240000.0	-378600000.0
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	2672.9	1941.2	1227.9	772.2

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	0.085	0.202	0.875	5.442
Percentage of DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	100.0	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanAmountsRecognizedInBalanceSheet us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanAmountsRecognizedInBalanceSheet

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-8635000.0	-23308000.0	-43285000.0	-64814000.0
Percentage of DefinedBenefitPlanAmountsRecognizedInBalanceSheet	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-90058000.0	-93394000.0	-136400000.0	-109090000.0
Percentage of DefinedBenefitPlanAmountsRecognizedInBalanceSheet	1042.9	400.7	315.1	168.3

us-gaap:DefinedBenefitPlanBenefitObligation us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanBenefitObligation

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	239	230	220	255	243
Percentage of DefinedBenefitPlanBenefitObligation	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	1077	1001	950	993	966
Percentage of DefinedBenefitPlanBenefitObligation	449.9	434.5	431.8	389.7	396.9

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	70	73	77
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	279	280	295
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	397.4	380.2	380.1

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	16	16	16
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	51	49	52
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	318.9	301.5	312.7

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	15	15	16
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	54	53	56
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	357.1	339.9	343.9

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	15	16	16
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	53	52	55
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	346.3	327.1	334.1

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	15	16	16
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	52	51	54
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	333.1	316.8	326.1

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	15	16	16
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	51	50	53
Percentage of DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	324.9	308.9	318.6

us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31
Value	1100000.0	1100000.0	1000000.0
Percentage of DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	100.0	100.0	100.0

us-gaap:DefinedBenefitPlanFundedStatusOfPlan us-gaap:RetirementPlanType

us-gaap:DefinedBenefitPlanFundedStatusOfPlan

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-8635000.0	-23308000.0	-43285000.0	-64814000.0
Percentage of DefinedBenefitPlanFundedStatusOfPlan	100.0	100.0	100.0	100.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	-90058000.0	-93394000.0	-136400000.0	-109090000.0
Percentage of DefinedBenefitPlanFundedStatusOfPlan	1042.9	400.7	315.1	168.3

us-gaap:DerivativeNonmonetaryNotionalAmount

Period End	2021-06-30	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2018-12-31
Value	16.1	14.7	35400.0	14700.0	0	14300.0	35500.0	14300.0
Percentage of DerivativeNonmonetaryNotionalAmount	100.0	100.0	100.0	100.0	0.0	100.0	100.0	100.0

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized us-gaap:AwardType

us-gaap:EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized

us-gaap:PerformanceShares

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	6700000.0	6400000.0	5800000.0	5100000.0	4800000.0	4700000.0	4900000.0
Percentage of EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RestrictedStockUnitsRSU

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	3100000.0	3000000.0	2600000.0	2600000.0	2800000.0	3200000.0	2800000.0
Percentage of EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	46.3	46.9	44.8	51.0	58.3	68.1	57.1

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue us-gaap:DefinedBenefitPlanByPlanAssetCategories, us-gaap:RetirementPlanType

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue

ogs:Insurancecontractsandgroupannuitycontracts, us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	24	25	30	35	45
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	100.0	100.0	100.0	100.0	100.0

us-gaap:OtherInvestments, us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	87	81	79	78	57
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	356.2	314.7	260.2	223.9	127.1

us-gaap:FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue us-gaap:RetirementPlanType

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31
Value	112	107	109	113	102
Percentage of FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue	456.2	414.7	360.2	323.9	227.1

us-gaap:InterestPayableCurrent

Period End	2021-06-30	2020-12-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2014-12-31	2014-06-30	2013-12-31
Value	25	20	18	7.867	19	7.667	18	7.742	18	7.667	18	7.691	18	7.654	18	7.647	18	18	19	0.129
Percentage of InterestPayableCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths

Period End	2020-12-31
Value	7900000.0
Percentage of LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	100.0

us-gaap:LineOfCreditFacilityRemainingBorrowingCapacity

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30
Value	998	998	948	698
Percentage of LineOfCreditFacilityRemainingBorrowingCapacity	100.0	100.0	100.0	100.0

us-gaap:LongTermDebtFairValue us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:LongTermDebtFairValue

us-gaap:FairValueInputsLevel2

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2014-12-31
Value	4300	4200	2000	1900	1500	1500	1500	1500	0.0	1400	1200	1200	1300	1300	1300	1300	1200	1200	1300	1300	1300	1200	1200	1200	1300
Percentage of LongTermDebtFairValue	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:MaterialsSuppliesAndOther

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2014-12-31	2013-12-31
Value	52	51	52	55	54	53	55	56	50	46	44	40	36	35	39	38	36	34	34	30	32	29	33	33	31	27	16
Percentage of MaterialsSuppliesAndOther	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:NetRegulatoryAssets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1799	1830	-139.595	-139.847	-163.076	-107.365	-110.243	-85.482	-92.735	-98.256	-77.361	-139.284	-144.618	-118.382	-35.49	500	488	490	511	484	439	437	435	418	422	418	480	312	317	326	6.308
Percentage of NetRegulatoryAssets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities us-gaap:RetirementPlanType

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	1056000.0	1045000.0	962000.0	963000.0
Percentage of PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesInventory

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	85	44	93	105	72	48	104	118	88	51	107	126	80	50	130	157	114	91	125	144	103	80	142	159	119	81	185	217	152	81	166
Percentage of PublicUtilitiesInventory	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2033	2004	1971	1955	1926	1901	1867	1847	1840	1816	1789	1768	1745	1726	1706	1730	1710	1694	1672	1658	1647	1639	1620	1604	1590	1578	1556	1545	1530	1516	1489
Percentage of PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	1971	1867	1789	1706	1672	1620	1556	1489
Percentage of PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	4989	4910	4867	4779	4707	4634	4565	4488	4400	4331	4283	4195	4125	4056	4007	3912	3834	3773	3731	3680	3611	3557	3511	3435	3380	3325	3293	3237	3174	3112	3044
Percentage of PublicUtilitiesPropertyPlantAndEquipmentNet	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentNet us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	4867	4565	4283	4007	3731	3511	3293	3044
Percentage of PublicUtilitiesPropertyPlantAndEquipmentNet	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentPlantInService

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	7023	6915	6838	6735	6633	6536	6433	6336	6241	6148	6073	5964	5870	5782	5713	5643	5545	5468	5404	5338	5259	5196	5132	5040	4970	4904	4850	4782	4704	4628	4534
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentPlantInService us-gaap:PropertyPlantAndEquipmentByType, us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:ConstructionInProgress, us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	77	152	126	130	70	57	71	74
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	1.1	2.4	2.1	2.3	1.3	1.1	1.5	1.6

us-gaap:GasDistributionEquipment, us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	5517	5117	4861	4572	4321	4114	3909	3703
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	80.7	79.5	80.0	80.0	80.0	80.2	80.6	81.7

us-gaap:GasTransmissionEquipment, us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	586	549	517	497	481	462	450	430
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	8.6	8.5	8.5	8.7	8.9	9.0	9.3	9.5

us-gaap:LandBuildingsAndImprovements, us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	657	612	567	513	530	498	418	326
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	9.6	9.5	9.3	9.0	9.8	9.7	8.6	7.2

us-gaap:PublicUtilitiesPropertyPlantAndEquipmentPlantInService us-gaap:PublicUtilityRegulatedOrUnregulatedStatus

us-gaap:RegulatedOperation

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	6838	6433	6073	5713	5404	5132	4850	4534
Percentage of PublicUtilitiesPropertyPlantAndEquipmentPlantInService	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RatioOfIndebtednessToNetCapital1

Period End	2020-09-30
Value	46.0
Percentage of RatioOfIndebtednessToNetCapital1	100.0

us-gaap:RegulatoryAssets us-gaap:RegulatoryAsset

us-gaap:RegulatoryAssets

ogs:Advaloremtax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2018-12-31
Value	6.312	4.834	5.558	5.26	4.095	3.593	2.921	2.572	2.083	1.07
Percentage of RegulatoryAssets	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:CustomerCreditDeferrals

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30
Value	17	19	10	14
Percentage of RegulatoryAssets	284.1	402.4	184.7	283.3

ogs:MGPCostsMember

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31
Value	18	18	18	11	11	9.783	9.807	9.832	9.856	7.709	7.724	7.724	7.724	6.11	6.104
Percentage of RegulatoryAssets	297.2	388.6	338.4	223.1	287.1	272.3	335.7	382.3	473.2	0.0	721.9	0.0	0.0	0.0	0.0

ogs:Otherregulatoryassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	3.799	2.963	4.302	5.18	12	12	7.608	11	13	16	5.613	8.284	9.275	10	7.718	8.59	7.979	9.049	8.24	8.679	7.122	7.499	2.678	2.936	2.722	3.432	4.87	5.974	5.464	6.209	11
Percentage of RegulatoryAssets	60.2	61.3	77.4	98.5	307.0	346.6	260.5	445.6	656.2	0.0	524.6	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:Totalregulatoryassetsnetofamortization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2381	2390	423	435	421	420	438	470	462	468	491	424	424	444	493	511	503	504	523	504	465	464	468	472	474	487	528	363	354	363	45
Percentage of RegulatoryAssets	37729.3	49457.2	7623.8	8286.4	10285.8	11703.1	15011.2	18283.9	22212.0	0.0	45971.9	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:Underrecoveredpurchasedgascosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	5.245	1992	16	22	7.247	17	18	0.767	25	16	6.741	12	41	43	26	17	29	29	10	1.092	13	10	28	36	16	14	12
Percentage of RegulatoryAssets	83.1	41209.6	296.9	427.5	177.0	587.9	702.1	36.8	2344.2	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:Weathernormalization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31
Value	1.12	0.628	4.806	4.289	4.674	3.713	4.76	17	19	20	19	17	17	18	15	2.198
Percentage of RegulatoryAssets	17.7	13.0	86.5	81.5	114.1	103.3	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:WinterWeatherEventCosts

Period End	2021-06-30
Value	1987
Percentage of RegulatoryAssets	31494.6

us-gaap:LossOnReacquiredDebt

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	5.273	5.475	5.678	5.88	6.083	6.286	6.489	6.691	6.894	7.097	7.299	7.502	7.704	7.907	8.11	8.312	8.515	8.718	8.92	9.124	9.326	9.529	9.731	9.934	10	10	10	10	10	11	11
Percentage of RegulatoryAssets	83.5	113.3	102.2	111.8	148.5	175.0	222.1	260.1	331.0	0.0	682.1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:PensionCosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	335	346	357	366	374	384	394	421	429	437	445	382	392	402	412	430	440	449	458	441	420	430	440	448	461	473	484	310	321	331	9.854
Percentage of RegulatoryAssets	5308.8	7169.0	6437.7	6960.8	9151.9	10706.0	13504.9	16393.8	20614.8	0.0	41599.1	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:RegulatoryAssets us-gaap:RetirementPlanType

us-gaap:OtherPostretirementBenefitPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	13	19	33	43
Percentage of RegulatoryAssets	234.8	666.1	3109.3	0.0

us-gaap:PensionPlansDefinedBenefit

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31
Value	341	373	412	369
Percentage of RegulatoryAssets	6137.5	12770.5	38555.6	0.0

us-gaap:RegulatoryAssetsCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	50	43	56	71	47	39	47	54	38	38	54	49	39	49	88	99	82	74	83	73	54	42	32	31	21	22	50	51	31	29	21
Percentage of RegulatoryAssetsCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatoryAssetsCurrent us-gaap:RegulatoryAsset

ogs:Advaloremtax

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2018-12-31
Value	6.312	4.834	5.558	5.26	4.095	3.593	2.921	2.572	2.083	1.07
Percentage of RegulatoryAssetsCurrent	12.4	11.0	9.8	7.3	8.5	9.0	6.2	4.8	5.4	2.0

ogs:CustomerCreditDeferrals

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30
Value	17	19	10	14
Percentage of RegulatoryAssetsCurrent	35.3	44.3	18.1	20.8

ogs:MGPCostsMember

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31
Value	0.098	0.098	0.098	0.098	0.098	0.098	0.098	0.098	0.098	0.098	0.0	0.0	0.0	0.0	0.0
Percentage of RegulatoryAssetsCurrent	0.2	0.2	0.2	0.1	0.2	0.2	0.2	0.2	0.3	0.3	0.0	0.0	0.0	0.0	0.0

ogs:Otherregulatoryassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2.721	1.606	2.189	2.773	9.879	10	5.224	9.617	11	14	4.071	5.362	6.078	6.159	3.513	3.591	3.181	4.019	3.274	2.232	2.056	2.101	0.909	1.092	0.718	1.292	2.561	3.332	2.752	3.369	8.154
Percentage of RegulatoryAssetsCurrent	5.4	3.7	3.9	3.9	20.6	26.1	11.0	17.8	30.4	38.4	7.5	10.9	15.4	12.5	4.0	3.6	3.9	5.4	3.9	3.0	3.8	4.9	2.8	3.4	3.4	5.8	5.1	6.4	8.7	11.3	37.7

ogs:Totalregulatoryassetsnetofamortization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	50	43	56	71	47	39	47	54	38	38	54	49	39	49	88	99	82	74	83	73	54	42	32	31	21	22	50	51	31	29	21
Percentage of RegulatoryAssetsCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Underrecoveredpurchasedgascosts

Period End	2021-06-30	2020-12-31	2020-09-30	2020-06-30	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	5.245	16	22	7.247	17	18	0.767	25	16	6.741	12	41	43	26	17	29	29	10	1.092	13	10	28	36	16	14	12
Percentage of RegulatoryAssetsCurrent	10.3	29.1	31.3	15.1	36.2	33.4	2.0	46.1	34.1	17.1	25.3	46.8	44.2	32.2	24.0	36.0	39.4	19.5	2.6	40.5	32.7	57.2	70.0	52.0	46.8	57.2

ogs:Weathernormalization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31
Value	1.12	0.628	4.806	4.289	4.674	3.713	4.76	17	19	20	19	17	17	18	15	2.198
Percentage of RegulatoryAssetsCurrent	2.2	1.4	8.5	6.0	9.7	9.3	9.7	19.8	19.7	24.7	26.5	21.2	23.0	33.2	36.7	6.7

us-gaap:PensionCosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	16	16	16	21	21	21	21	22	22	22	23	25	25	25	25	31	31	32	31	24	22	23	15	19	19	20	18	11	11	11	0.298
Percentage of RegulatoryAssetsCurrent	32.5	37.6	29.1	29.5	44.1	53.3	44.7	42.4	59.9	59.3	43.0	51.2	63.7	50.9	28.5	31.7	38.3	43.0	37.9	33.4	42.1	53.9	47.6	61.3	92.8	90.6	36.1	22.0	36.7	39.2	1.4

us-gaap:RegulatoryAssetsNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2330	2346	366	364	373	380	391	416	424	429	437	375	385	394	405	411	421	430	440	431	410	421	435	440	452	465	478	312	322	333	23
Percentage of RegulatoryAssetsNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatoryAssetsNoncurrent ogs:OtherEmployeeBenefitPlans

ogs:NonserviceCosts

Period End	2020-12-31	2019-12-31	2018-12-31
Value	6.0	4.7	1.5
Percentage of RegulatoryAssetsNoncurrent	1.6	1.2	0.3

us-gaap:RegulatoryAssetsNoncurrent us-gaap:RegulatoryAsset

ogs:MGPCostsMember

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-01-01
Value	18	18	18	11	11	9.685	9.709	9.734	9.758	7.611	7.724	7.724	7.724	6.11	6.104	5.9
Percentage of RegulatoryAssetsNoncurrent	0.8	0.8	5.1	3.2	3.1	2.5	2.5	2.3	2.3	1.8	1.8	2.1	2.0	1.5	1.5	0.0

ogs:Otherregulatoryassets

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1.078	1.357	2.113	2.407	2.694	2.06	2.384	1.844	2.023	1.369	1.542	2.922	3.197	3.934	4.205	4.999	4.798	5.03	4.966	6.447	5.066	5.398	1.769	1.844	2.004	2.14	2.309	2.642	2.712	2.84	3.725
Percentage of RegulatoryAssetsNoncurrent	0.0	0.1	0.6	0.7	0.7	0.5	0.6	0.4	0.5	0.3	0.4	0.8	0.8	1.0	1.0	1.2	1.1	1.2	1.1	1.5	1.2	1.3	0.4	0.4	0.4	0.5	0.5	0.8	0.8	0.9	15.6

ogs:Totalregulatoryassetsnetofamortization

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	2330	2346	366	364	373	380	391	416	424	429	437	375	385	394	405	411	421	430	440	431	410	421	435	440	452	465	478	312	322	333	23
Percentage of RegulatoryAssetsNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Underrecoveredpurchasedgascosts

Period End	2021-03-31	2020-06-30	2019-12-31	2019-09-30	2019-06-30	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	1992	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Percentage of RegulatoryAssetsNoncurrent	84.9	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:WinterWeatherEventCosts

Period End	2021-06-30
Value	1987
Percentage of RegulatoryAssetsNoncurrent	85.3

us-gaap:LossOnReacquiredDebt

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	4.461	4.663	4.866	5.068	5.271	5.474	5.677	5.879	6.082	6.285	6.487	6.69	6.892	7.095	7.298	7.5	7.703	7.906	8.108	8.312	8.514	8.717	8.919	9.122	9.325	9.527	9.73	9.933	10	10	10
Percentage of RegulatoryAssetsNoncurrent	0.2	0.2	1.3	1.4	1.4	1.4	1.5	1.4	1.4	1.5	1.5	1.8	1.8	1.8	1.8	1.8	1.8	1.8	1.8	1.9	2.1	2.1	2.0	2.1	2.1	2.0	2.0	3.2	3.1	3.1	44.2

us-gaap:PensionCosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	318	330	341	345	353	363	373	398	406	414	421	357	367	377	387	399	408	417	427	416	397	407	425	429	441	453	466	299	309	319	9.556
Percentage of RegulatoryAssetsNoncurrent	13.7	14.1	93.0	94.8	94.7	95.5	95.5	95.8	95.8	96.4	96.4	95.4	95.4	95.7	95.7	97.0	97.0	97.0	97.0	96.6	96.7	96.7	97.5	97.5	97.5	97.5	97.5	96.0	96.0	96.0	40.1

us-gaap:RegulatoryLiabilities us-gaap:RegulatoryLiability

us-gaap:RegulatoryLiabilities

ogs:Federalincometaxratechanges

Period End	2020-12-31	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31
Value	547	500	513	521	524	544	551	541	537	530	519
Percentage of RegulatoryLiabilities	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:IncometaxratechangesMemberDomain

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2019-12-31
Value	558	537	547	555	560	513
Percentage of RegulatoryLiabilities	0.0	0.0	100.0	0.0	0.0	100.0

ogs:Overrecoveredpurchasedgascosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	23	23	15	20	23	27	27	27	22	14	13	31	31	9.434	10	14	12	10	11	18	18	22	33	35	44	13	13	17	15	17
Percentage of RegulatoryLiabilities	0.0	0.0	2.9	0.0	0.0	5.5	5.4	5.3	4.3	2.6	2.5	5.8	6.0	1.8	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

ogs:Totalregulatedliabilities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	582	560	563	575	584	527	548	555	555	566	569	563	569	562	528	10	14	13	11	20	25	27	33	53	51	69	47	50	36	36	39
Percentage of RegulatoryLiabilities	0.0	0.0	102.9	0.0	0.0	105.5	106.8	106.6	105.9	104.1	103.2	104.1	105.9	106.0	101.8	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:RegulatoryLiabilityCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2013-12-31
Value	23	23	15	20	26	33	45	48	46	54	48	41	47	44	9.438	11	13	19	20	24	41	37	54	32	33	17	17
Percentage of RegulatoryLiabilityCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RegulatoryLiabilityCurrent us-gaap:RegulatoryLiability

ogs:Overrecoveredpurchasedgascosts

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	23	23	15	20	23	27	27	27	22	14	13	31	31	9.434	10	14	12	10	11	18	18	22	33	35	44	13	13	17	15	17
Percentage of RegulatoryLiabilityCurrent	100.0	100.0	100.0	100.0	91.3	81.3	61.1	56.5	48.6	25.9	28.2	65.7	71.8	100.0	0.0	0.0	0.0	85.2	87.4	92.4	93.8	93.0	80.7	94.7	81.1	40.2	39.9	100.0	0.0	100.0

ogs:Totalregulatedliabilities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	23	23	15	20	26	33	45	48	46	54	48	41	47	44	9.438	10	14	13	11	13	19	20	24	41	37	54	32	33	17	15	17
Percentage of RegulatoryLiabilityCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	100.0

us-gaap:RegulatoryLiabilityNoncurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2016-12-31
Value	558	537	547	555	558	494	503	506	508	511	520	521	521	518	519	0.0
Percentage of RegulatoryLiabilityNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0

us-gaap:RegulatoryLiabilityNoncurrent us-gaap:RegulatoryLiability

ogs:Federalincometaxratechanges

Period End	2020-12-31	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31
Value	547	494	503	506	508	511	520	521	521	518	519
Percentage of RegulatoryLiabilityNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

ogs:IncometaxratechangesMemberDomain

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2019-12-31
Value	558	537	547	555	558	503
Percentage of RegulatoryLiabilityNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0

ogs:Totalregulatedliabilities

Period End	2021-06-30	2021-03-31	2020-12-31	2020-09-30	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2017-09-30	2017-06-30	2017-03-31	2016-12-31	2016-09-30	2016-06-30	2016-03-31	2015-12-31	2015-09-30	2015-06-30	2015-03-31	2014-12-31	2014-09-30	2014-06-30	2014-03-31	2013-12-31
Value	558	537	547	555	558	494	503	506	508	511	520	521	521	518	519	0.0	0.0	0.0	0.0	7.019	6.123	6.923	9.032	11	14	15	15	17	18	21	21
Percentage of RegulatoryLiabilityNoncurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber

us-gaap:PerformanceShares

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	208520.0	218180.0	219330.0	237320.0	288810.0	439250.0	847950.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RestrictedStockUnitsRSU

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	99800.0	104400.0	109510.0	140660.0	194900.0	231260.0	325730.0
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber	47.9	47.9	49.9	59.3	67.5	52.6	38.4

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue us-gaap:AwardType

us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue

us-gaap:PerformanceShares

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	87.97	77.58	69.21	57.78	46.06	27.35	17.62
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	100.0	100.0	100.0	100.0	100.0	100.0	100.0

us-gaap:RestrictedStockUnitsRSU

Period End	2020-12-31	2019-12-31	2018-12-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31
Value	82.29	72.21	63.45	51.97	41.68	32.59	23.47
Percentage of ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue	93.5	93.1	91.7	89.9	90.5	119.2	133.2

us-gaap:UnbilledReceivablesCurrent

Period End	2021-06-30	2021-03-31	2020-12-31	2020-06-30	2020-03-31	2019-12-31	2019-09-30	2019-06-30	2019-03-31	2018-12-31	2018-09-30	2018-06-30	2018-03-31	2017-12-31	2016-12-31	2015-12-31	2014-12-31	2013-12-31
Value	57	91	144	49	71	109	53	48	88	127	54	52	84	138	143	109	141	143
Percentage of UnbilledReceivablesCurrent	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0	100.0

Line plots across dimensions of each concept

us-gaap:OtherNonoperatingIncomeExpense
ogs:OTHERINCOMEANDOTHEREXPENSE
(None,)

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents
(None,)

us-gaap:PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent
us-gaap:RetirementPlanType
(None,)

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents
(None,)

us-gaap:StockIssuedDuringPeriodValueNewIssues
us-gaap:StatementEquityComponents
(None,)

us-gaap:DebtInstrumentInterestRateStatedPercentage
us-gaap:LongtermDebtType
(None,)

OGS

Table of contents

Plots across concepts

Tables

Common Stock Value

us-gaap:CommonStockValue

us-gaap:CommonStockValue

Preferred Stock Par Or Stated Value Per Share

us-gaap:PreferredStockParOrStatedValuePerShare

us-gaap:PreferredStockParOrStatedValuePerShare

Shares Issued

us-gaap:SharesIssued us-gaap:StatementEquityComponents

us-gaap:SharesIssued

us-gaap:CommonStock

Common Stock Shares Issued

us-gaap:CommonStockSharesIssued

us-gaap:CommonStockSharesIssued

us-gaap:CommonStockSharesIssued us-gaap:StatementEquityComponents

us-gaap:CommonStock

Common Stock Shares Authorized

us-gaap:CommonStockSharesAuthorized

us-gaap:CommonStockSharesAuthorized

Common Stock Shares Outstanding

us-gaap:CommonStockSharesOutstanding

us-gaap:CommonStockSharesOutstanding

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareBasic

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted

us-gaap:EarningsPerShareDiluted

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:ComprehensiveIncomeNetOfTax

Cost Of Goods And Services Sold

us-gaap:CostOfGoodsAndServicesSold

us-gaap:CostOfGoodsAndServicesSold

Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit

us-gaap:IncomeTaxExpenseBenefit

Interest Expense

us-gaap:InterestExpense

us-gaap:InterestExpense

Net Income Loss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss

us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings

Operating Income Loss

us-gaap:OperatingIncomeLoss

us-gaap:OperatingIncomeLoss

Other Comprehensive Income Loss Net Of Tax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax

us-gaap:OtherComprehensiveIncomeLossNetOfTax us-gaap:StatementEquityComponents

us-gaap:AccumulatedOtherComprehensiveIncome

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherNonoperatingIncomeExpense ogs:OTHERINCOMEANDOTHEREXPENSE

ogs:Netperiodiccostotherthanservicecost

ogs:Othernet

Regulated Operating Revenue

us-gaap:RegulatedOperatingRevenue

us-gaap:RegulatedOperatingRevenue

Assets

us-gaap:Assets

us-gaap:Assets

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:LiabilitiesAndStockholdersEquity