Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pre- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	$ 351	$ (655)	$ 674	$ (452)
Less: reclassification adjustment of realized capital gains and losses	(8)	62	(55)	156
Unrealized net capital gains and losses	359	(717)	729	(608)
Unrealized foreign currency translation adjustments	9	(8)	6	(11)
Other comprehensive income (loss)	368	(725)	735	(619)
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(123)	229	(236)	158
Less: reclassification adjustment of realized capital gains and losses	3	(22)	19	(55)
Unrealized net capital gains and losses	(126)	251	(255)	213
Unrealized foreign currency translation adjustments	(3)	3	(2)	4
Other comprehensive income (loss)	(129)	254	(257)	217
After- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	228	(426)	438	(294)
Less: reclassification adjustment of realized capital gains and losses	(5)	40	(36)	101
Unrealized net capital gains and losses	233	(466)	474	(395)
Unrealized foreign currency translation adjustments	6	(5)	4	(7)
Other comprehensive income (loss), after-tax	$ 239	$ (471)	$ 478	$ (402)