Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 2,674	$ 815	$ 718	$ 1,837
Cumulative effect of change in accounting principle, net of income tax					$ (4)
Restated balance, beginning of period	3,532	815	3,532	560	1,837
OCI before reclassifications	1,105	(313)	3,651	(1,607)
Deferred income tax benefit (expense)	(233)	64	(766)	355
AOCI before reclassifications, net of income tax	3,546	566	3,603	506
Amounts reclassified from AOCI	(18)	(9)	(90)	71
Deferred income tax benefit (expense)	4	3	19	(17)
Amounts reclassified from AOCI, net of income tax	(14)	(6)	(71)	54
Balance, end of period	3,532	560	3,532	560
Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	2,521	671	564	1,709
Cumulative effect of change in accounting principle, net of income tax					(79)
Restated balance, beginning of period	2,521	671	3,259	463	1,709
OCI before reclassifications	952	(298)	3,452	(1,633)
Deferred income tax benefit (expense)	(200)	61	(725)	361
AOCI before reclassifications, net of income tax	3,273	434	3,291	358
Amounts reclassified from AOCI	(17)	37	(40)	136
Deferred income tax benefit (expense)	3	(8)	8	(31)
Amounts reclassified from AOCI, net of income tax	(14)	29	(32)	105
Balance, end of period	3,259	463	3,259	463
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	172	162	180	151
Cumulative effect of change in accounting principle, net of income tax					0
Restated balance, beginning of period	172	162	296	151	151
OCI before reclassifications	157	(7)	196	28
Deferred income tax benefit (expense)	(33)	2	(41)	(6)
AOCI before reclassifications, net of income tax	296	157	335	173
Amounts reclassified from AOCI	(1)	(46)	(50)	(65)
Deferred income tax benefit (expense)	1	11	11	14
Amounts reclassified from AOCI, net of income tax	0	(35)	(39)	(51)
Balance, end of period	296	122	296	122
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(19)	(18)	(26)	(23)
Cumulative effect of change in accounting principle, net of income tax					0
Restated balance, beginning of period	(19)	(18)	(26)	(25)	(23)
OCI before reclassifications	(4)	(8)	3	(2)
Deferred income tax benefit (expense)	0	1	0	0
AOCI before reclassifications, net of income tax	(23)	(25)	(23)	(25)
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	$ (23)	$ (25)	$ (23)	(25)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative effect of change in accounting principle, net of income tax					(79)
Restatement Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period				1,758
Restated balance, beginning of period				1,758	1,758
Restatement Adjustment | Unrealized Investment Gains (Losses), Net of Related Offsets (1)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period				1,630
Restated balance, beginning of period				1,630	1,630
Restatement Adjustment | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period				151
Restated balance, beginning of period				151	151
Restatement Adjustment | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period				(23)
Restated balance, beginning of period				$ (23)	$ (23)