Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 4,965	$ 2,702	$ 3,240	$ 716
OCI before reclassifications	529	1,127	2,717	3,717
Deferred income tax benefit (expense)	(111)	(237)	(579)	(780)
AOCI before reclassifications, net of income tax	5,383	3,592	5,378	3,653
Amounts reclassified from AOCI	(3)	(31)	4	(108)
Deferred income tax benefit (expense)	1	6	(1)	22
Amounts reclassified from AOCI, net of income tax	(2)	(25)	3	(86)
Balance, end of period	5,381	3,567	5,381	3,567
Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	4,517	2,564	3,111	576
OCI before reclassifications	707	970	2,475	3,515
Deferred income tax benefit (expense)	(149)	(204)	(520)	(738)
AOCI before reclassifications, net of income tax	5,075	3,330	5,066	3,353
Amounts reclassified from AOCI	8	(30)	20	(59)
Deferred income tax benefit (expense)	(1)	6	(4)	12
Amounts reclassified from AOCI, net of income tax	7	(24)	16	(47)
Balance, end of period	5,082	3,306	5,082	3,306
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	500	181	172	187
OCI before reclassifications	(185)	160	235	201
Deferred income tax benefit (expense)	39	(33)	(49)	(42)
AOCI before reclassifications, net of income tax	354	308	358	346
Amounts reclassified from AOCI	(11)	(1)	(16)	(49)
Deferred income tax benefit (expense)	2	0	3	10
Amounts reclassified from AOCI, net of income tax	(9)	(1)	(13)	(39)
Balance, end of period	345	307	345	307
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(24)	(20)	(15)	(27)
OCI before reclassifications	9	(3)	9	4
Deferred income tax benefit (expense)	(1)	0	(10)	0
AOCI before reclassifications, net of income tax	(16)	(23)	(16)	(23)
Amounts reclassified from AOCI	0	0	0	0
Deferred income tax benefit (expense)	0	0	0	0
Amounts reclassified from AOCI, net of income tax	0	0	0	0
Balance, end of period	(16)	(23)	(16)	(23)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(28)	(23)	(28)	(20)
OCI before reclassifications	(2)	0	(2)	(3)
Deferred income tax benefit (expense)	0	0	0	0
AOCI before reclassifications, net of income tax	(30)	(23)	(30)	(23)
Amounts reclassified from AOCI	0	0	0	0
Deferred income tax benefit (expense)	0	0	0	0
Amounts reclassified from AOCI, net of income tax	0	0	0	0
Balance, end of period	$ (30)	$ (23)	(30)	$ (23)
Cumulative Effect, Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period			$ 3