Capital Accounts, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ 365	$ 286
Other comprehensive income (loss) for period, before reclassifications	57	280
Reclassification of losses (gains) to net income during period	(115)	(201)
Total other comprehensive income (loss) for period	(58)	79	$ 451
Accumulated Other Comprehensive Income (Loss), Ending balance	307	365	286
Interest expense	1,269	1,244	1,283
Revenue	(49,715)	(58,186)	(40,807)
Operating costs and expenses	43,017	51,502	35,078
Total	(5,657)	(5,615)	(4,755)
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	93	254
Reclassification of losses (gains) to net income during period	(110)	(220)
Total other comprehensive income (loss) for period	(17)	34
Accumulated Other Comprehensive Income (Loss), Ending balance	154	171	137
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	(36)	26
Reclassification of losses (gains) to net income during period	(5)	19
Total other comprehensive income (loss) for period	(41)	45
Accumulated Other Comprehensive Income (Loss), Ending balance	151	192	147
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	$ 2
Reclassification of Losses (Gains) out of Accumulated Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total	(115)	(201)
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	(106)	(181)
Operating costs and expenses	(4)	(39)
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	$ (5)	$ 19