Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pre- tax
Other comprehensive (loss) income	$ (448)	$ 25	$ 240
Tax
Other comprehensive (loss) income	94	(9)	(83)
After- tax
Other comprehensive (loss) income, after-tax	(354)	16	157
Accumulated Net Investment Gain (Loss)
Pre- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(483)	51	134
Less: reclassification adjustment of realized capital gains and losses	(35)	43	(100)
Other comprehensive (loss) income	(448)	8	234
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	101	(18)	(46)
Less: reclassification adjustment of realized capital gains and losses	7	(15)	35
Other comprehensive (loss) income	94	(3)	(81)
After- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(382)	33	88
Less: reclassification adjustment of realized capital gains and losses	(28)	28	(65)
Other comprehensive (loss) income, after-tax	(354)	5	153
Accumulated Foreign Currency Adjustment
Pre- tax
Other comprehensive (loss) income	0	17	6
Tax
Other comprehensive (loss) income	0	(6)	(2)
After- tax
Other comprehensive (loss) income, after-tax	$ 0	$ 11	$ 4

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