Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pre- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	$ 329	$ 212
Less: reclassification adjustment of realized capital gains and losses	(41)	103
Unrealized net capital gains and losses	370	109
Unrealized foreign currency translation adjustments	(3)	(3)
Other comprehensive income	367	106
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(115)	(74)
Less: reclassification adjustment of realized capital gains and losses	14	(36)
Unrealized net capital gains and losses	(129)	(38)
Unrealized foreign currency translation adjustments	1	1
Other comprehensive (loss) income	(128)	(37)
After- tax
Unrealized net holding gains and losses arising during the period, net of related offsets	214	138
Less: reclassification adjustment of realized capital gains and losses	(27)	67
Unrealized net capital gains and losses	241	71
Unrealized foreign currency translation adjustments	(2)	(2)
Other comprehensive income, after-tax	$ 239	$ 69