Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pre- tax
Other comprehensive income (loss)	$ 837	$ (448)	$ 25
Tax
Other comprehensive income (loss)	(175)	94	(9)
After- tax
Other comprehensive income (loss), after-tax	662	(354)	16
Accumulated Net Investment Gain (Loss)
Pre- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	878	(483)	51
Less: reclassification adjustment of realized capital gains and losses	19	(35)	43
Other comprehensive income (loss)	859	(448)	8
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(184)	101	(18)
Less: reclassification adjustment of realized capital gains and losses	(4)	7	(15)
Other comprehensive income (loss)	(180)	94	(3)
After- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	694	(382)	33
Less: reclassification adjustment of realized capital gains and losses	15	(28)	28
Other comprehensive income (loss), after-tax	679	(354)	5
Accumulated Foreign Currency Adjustment
Pre- tax
Other comprehensive income (loss)	(22)	0	17
Tax
Other comprehensive income (loss)	5	0	(6)
After- tax
Other comprehensive income (loss), after-tax	$ (17)	$ 0	$ 11