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	$ 4,610	$ 2,674	$ 3,215	$ 718
OCI before reclassifications	635	1,105	2,405	3,651
Deferred income tax benefit (expense)	(134)	(233)	(514)	(766)
AOCI before reclassifications, net of income tax	5,111	3,546	5,106	3,603
Amounts reclassified from AOCI	(4)	(18)	3	(90)
Deferred income tax benefit (expense)	1	4	(1)	19
Amounts reclassified from AOCI, net of income tax	(3)	(14)	2	(71)
Balance, end of period	5,108	3,532	5,108	3,532
Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	4,148	2,521	3,066	564
OCI before reclassifications	810	952	2,166	3,452
Deferred income tax benefit (expense)	(171)	(200)	(455)	(725)
AOCI before reclassifications, net of income tax	4,787	3,273	4,777	3,291
Amounts reclassified from AOCI	5	(17)	18	(40)
Deferred income tax benefit (expense)	(1)	3	(4)	8
Amounts reclassified from AOCI, net of income tax	4	(14)	14	(32)
Balance, end of period	4,791	3,259	4,791	3,259
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	485	172	163	180
OCI before reclassifications	(183)	157	231	196
Deferred income tax benefit (expense)	39	(33)	(48)	(41)
AOCI before reclassifications, net of income tax	341	296	346	335
Amounts reclassified from AOCI	(9)	(1)	(15)	(50)
Deferred income tax benefit (expense)	2	1	3	11
Amounts reclassified from AOCI, net of income tax	(7)	0	(12)	(39)
Balance, end of period	334	296	334	296
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(23)	(19)	(14)	(26)
OCI before reclassifications	8	(4)	8	3
Deferred income tax benefit (expense)	(2)	0	(11)	0
AOCI before reclassifications, net of income tax	(17)	(23)	(17)	(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	$ (17)	$ (23)	(17)	$ (23)
Cumulative Effect, Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period			$ 3