Capital Accounts, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance	$ 29,589	$ 28,759
Total other comprehensive income (loss) for period	49	(164)
Balance	29,775	28,477
Interest expense	340	331
Revenue	(15,417)	(14,760)
Operating costs and expenses	13,690	12,974
Total	(1,406)	(1,483)
Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance	143	151
Other comprehensive income (loss) for period, before reclassifications	2	2
Reclassification of losses (gains) to net income during period	(1)	(2)
Total other comprehensive income (loss) for period	1	0
Balance	144	151
Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance	91	154
Other comprehensive income (loss) for period, before reclassifications	22	(162)
Reclassification of losses (gains) to net income during period	26	(2)
Total other comprehensive income (loss) for period	48	(164)
Balance	139	(10)
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
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
Balance	2	2
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Balance	236	307
Other comprehensive income (loss) for period, before reclassifications	24	(160)
Reclassification of losses (gains) to net income during period	25	(4)
Total other comprehensive income (loss) for period	49	(164)
Balance	285	143
Reclassification of Losses (Gains) out of Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total	25	(4)
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	(1)	(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	14	(19)
Operating costs and expenses	$ 12	$ 17