Capital Accounts, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ 307	$ 365
Other comprehensive income (loss) for period, before reclassifications	(160)	(94)
Reclassification of losses (gains) to net income during period	(4)	(30)
Total other comprehensive income (loss) for period	(164)	(124)
Accumulated Other Comprehensive Income (Loss), Ending balance	143	241
Interest expense	331	314
Revenue	(14,760)	(12,444)
Operating costs and expenses	12,974	10,757
Total	(1,483)	(1,422)
Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	151	192
Other comprehensive income (loss) for period, before reclassifications	2	(5)
Reclassification of losses (gains) to net income during period	(2)	2
Total other comprehensive income (loss) for period	0	(3)
Accumulated Other Comprehensive Income (Loss), Ending balance	151	189
Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	154	171
Other comprehensive income (loss) for period, before reclassifications	(162)	(89)
Reclassification of losses (gains) to net income during period	(2)	(32)
Total other comprehensive income (loss) for period	(164)	(121)
Accumulated Other Comprehensive Income (Loss), Ending balance	(10)	50
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	(4)	(30)
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)	2
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	(19)	(24)
Operating costs and expenses	$ 17	$ (8)