Capital Accounts, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ 365	$ 286
Other comprehensive income (loss) for period, before reclassifications	(94)	(99)
Reclassification of losses (gains) to net income during period	(30)	53
Total other comprehensive income (loss) for period	(124)	(46)
Accumulated Other Comprehensive Income (Loss), Ending balance	241	240
Interest expense	314	319
Revenue	(12,444)	(13,008)
Operating costs and expenses	10,757	11,397
Total	(1,422)	(1,331)
Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	192	147
Other comprehensive income (loss) for period, before reclassifications	(5)	0
Reclassification of losses (gains) to net income during period	2	8
Total other comprehensive income (loss) for period	(3)	8
Accumulated Other Comprehensive Income (Loss), Ending balance	189	155
Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	171	137
Other comprehensive income (loss) for period, before reclassifications	(89)	(99)
Reclassification of losses (gains) to net income during period	(32)	45
Total other comprehensive income (loss) for period	(121)	(54)
Accumulated Other Comprehensive Income (Loss), Ending balance	50	83
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	2	2
Other comprehensive income (loss) for period, before reclassifications	0	0
Reclassification of losses (gains) to net income during period	0	0
Total other comprehensive income (loss) for period	0	0
Accumulated Other Comprehensive Income (Loss), Ending balance	2	2
Reclassification of Losses (Gains) out of Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total	(30)	53
Reclassification of Losses (Gains) out of Accumulated Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Interest expense	2	8
Reclassification of Losses (Gains) out of Accumulated Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Revenue	(24)	39
Operating costs and expenses	$ (8)	$ 6