Accumulated Other Comprehensive Income (Loss) (After-tax Changes by Component) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	$ (4,220)	$ (4,358)	$ (3,964)
Amounts arising during the year	332	(94)	(496)
Reclassifications from AOCI	153	232	102
Net OCI during the year	4,063	138	(394)
Balance at end of year	(157)	(4,220)	(4,358)
Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K, Utility Business
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 year	(1,158)	(1,425)	(1,533)
Amounts arising during the year	372	267	108
Reclassifications from AOCI	0	0	0
Net OCI during the year	1,158	267	108
Balance at end of year	0	(1,158)	(1,425)
Foreign Currency Translation Adjustments [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K, Utility Business
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI	786
Qualifying Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	0	(5)	(7)
Amounts arising during the year	(39)	(19)	(11)
Reclassifications from AOCI	25	24	13
Net OCI during the year	1	5	2
Balance at end of year	1	0	(5)
Qualifying Derivatives [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K, Utility Business
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI	15
Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(16)	(18)	(19)
Amounts arising during the year	0	(1)	(1)
Reclassifications from AOCI	2	3	2
Net OCI during the year	10	2	1
Balance at end of year	(6)	(16)	(18)
Prior Service Costs [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K, Utility Business
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 year	(3,046)	(2,910)	(2,405)
Amounts arising during the year	(1)	(341)	(592)
Reclassifications from AOCI	126	205	87
Net OCI during the year	2,894	(136)	(505)
Balance at end of year	(152)	$ (3,046)	$ (2,910)
Defined Benefit Plans Actuarial Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income (Loss) due to Sale of U.K, Utility Business
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications from AOCI	$ 2,769