Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pre- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	$ (655)	$ (16)	$ (452)	$ 474
Less: reclassification adjustment of realized capital gains and losses	62	(10)	156	(21)
Unrealized net capital gains and losses	(717)	(6)	(608)	495
Unrealized foreign currency translation adjustments	(8)	0	(11)	2
Other comprehensive (loss) income	(725)	(6)	(619)	497
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	229	6	158	(167)
Less: reclassification adjustment of realized capital gains and losses	(22)	4	(55)	7
Unrealized net capital gains and losses	251	2	213	(174)
Unrealized foreign currency translation adjustments	3	0	4	(1)
Other comprehensive (loss) income	254	2	217	(175)
After- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(426)	(10)	(294)	307
Less: reclassification adjustment of realized capital gains and losses	40	(6)	101	(14)
Unrealized net capital gains and losses	(466)	(4)	(395)	321
Unrealized foreign currency translation adjustments	(5)	0	(7)	1
Other comprehensive (loss) income, after-tax	$ (471)	$ (4)	$ (402)	$ 322