Accumulated Other Comprehensive Income (Loss) - After-tax Changes by Component (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (124)	$ (191)	$ (157)	$ (4,220)
Amounts arising during the period	(10)	(12)	12	315
Reclassifications from AOCI	4	20	15	144
Net OCI during the period	(6)	8	27	4,037
Balance at end of period	(130)	(183)	(130)	(183)
Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				3,578
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	0	0	0	(1,158)
Amounts arising during the period	0	0	0	372
Reclassifications from AOCI	0	0	0	0
Net OCI during the period	0	0	0	1,158
Balance at end of period	0	0	0	0
Foreign currency translation adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				786
Unrealized gains (losses) on qualifying derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	2	0	1	0
Amounts arising during the period	0	0	0	(39)
Reclassifications from AOCI	0	1	1	25
Net OCI during the period	0	1	1	1
Balance at end of period	2	1	2	1
Unrealized gains (losses) on qualifying derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				15
Defined benefit plans Prior service costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(6)	(15)	(6)	(16)
Amounts arising during the period	0	0	(1)	0
Reclassifications from AOCI	1	9	2	2
Net OCI during the period	1	9	1	10
Balance at end of period	(5)	(6)	(5)	(6)
Defined benefit plans Prior service costs [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				8
Defined benefit plans Actuarial gain (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(122)	(176)	(152)	(3,046)
Amounts arising during the period	(10)	(12)	11	(18)
Reclassifications from AOCI	3	10	12	117
Net OCI during the period	(7)	(2)	23	2,868
Balance at end of period	(129)	(178)	(129)	(178)
Defined benefit plans Actuarial gain (loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				2,769
Equity Investees' OCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	2	0	0	0
Amounts arising during the period	0	0	2	0
Reclassifications from AOCI	0	0	0	0
Net OCI during the period	0	0	2	0
Balance at end of period	$ 2	$ 0	$ 2	0
Equity Investees' OCI | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K. Utility Business [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI				$ 0