Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 3,215	$ 718
OCI before reclassifications	(962)	1,188
Deferred income tax benefit (expense)	202	(250)
AOCI before reclassifications, net of income tax	2,455	1,656
Amounts reclassified from AOCI	(12)	2
Deferred income tax benefit (expense)	2	0
Amounts reclassified from AOCI, net of income tax	(10)	2
Balance, end of period	2,445	1,658
Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	3,066	564
OCI before reclassifications	(1,509)	1,222
Deferred income tax benefit (expense)	318	(257)
AOCI before reclassifications, net of income tax	1,875	1,529
Amounts reclassified from AOCI	(10)	28
Deferred income tax benefit (expense)	2	(6)
Amounts reclassified from AOCI, net of income tax	(8)	22
Balance, end of period	1,867	1,551
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	163	180
OCI before reclassifications	553	(34)
Deferred income tax benefit (expense)	(116)	7
AOCI before reclassifications, net of income tax	600	153
Amounts reclassified from AOCI	(2)	(26)
Deferred income tax benefit (expense)	0	6
Amounts reclassified from AOCI, net of income tax	(2)	(20)
Balance, end of period	598	133
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(14)	(26)
OCI before reclassifications	(6)	0
Deferred income tax benefit (expense)	0	0
AOCI before reclassifications, net of income tax	(20)	(26)
Amounts reclassified from AOCI	0	0
Deferred income tax benefit (expense)	0	0
Amounts reclassified from AOCI, net of income tax	0	0
Balance, end of period	(20)	$ (26)
Cumulative Effect, Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 3