Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 2,647	$ 1,670	$ 3,240	$ 716
OCI before reclassifications	2,925	1,375	2,188	2,590
Deferred income tax benefit (expense)	(623)	(287)	(468)	(543)
AOCI before reclassifications, net of income tax	4,949	2,758	4,960	2,763
Amounts reclassified from AOCI	20	(70)	7	(77)
Deferred income tax benefit (expense)	(4)	14	(2)	16
Amounts reclassified from AOCI, net of income tax	16	(56)	5	(61)
Balance, end of period	4,965	2,702	4,965	2,702
Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	2,083	1,580	3,111	576
OCI before reclassifications	3,059	1,293	1,768	2,545
Deferred income tax benefit (expense)	(643)	(271)	(371)	(534)
AOCI before reclassifications, net of income tax	4,499	2,602	4,508	2,587
Amounts reclassified from AOCI	23	(48)	12	(29)
Deferred income tax benefit (expense)	(5)	10	(3)	6
Amounts reclassified from AOCI, net of income tax	18	(38)	9	(23)
Balance, end of period	4,517	2,564	4,517	2,564
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	612	140	172	187
OCI before reclassifications	(140)	75	420	41
Deferred income tax benefit (expense)	30	(16)	(88)	(9)
AOCI before reclassifications, net of income tax	502	199	504	219
Amounts reclassified from AOCI	(3)	(22)	(5)	(48)
Deferred income tax benefit (expense)	1	4	1	10
Amounts reclassified from AOCI, net of income tax	(2)	(18)	(4)	(38)
Balance, end of period	500	181	500	181
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(19)	(27)	(15)	(27)
OCI before reclassifications	5	7	0	7
Deferred income tax benefit (expense)	(10)	0	(9)	0
AOCI before reclassifications, net of income tax	(24)	(20)	(24)	(20)
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	(24)	(20)	(24)	(20)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(29)	(23)	(28)	(20)
OCI before reclassifications	1	0	0	(3)
Deferred income tax benefit (expense)	0	0	0	0
AOCI before reclassifications, net of income tax	(28)	(23)	(28)	(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	$ (28)	$ (23)	(28)	$ (23)
Cumulative Effect, Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period			$ 3