Investments (Details 7) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investments
Net unrealized gains related to changes in valuation of fixed income securities subsequent to impairment measurement date	$ 143	$ 164
Other-than-temporary impairment losses included in accumulated other comprehensive income
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings	(77)	(117)
Municipal
Other-than-temporary impairment losses included in accumulated other comprehensive income
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings	(5)	(5)
ABS
Other-than-temporary impairment losses included in accumulated other comprehensive income
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings	(10)	(10)
RMBS
Other-than-temporary impairment losses included in accumulated other comprehensive income
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings	(57)	(90)
CMBS
Other-than-temporary impairment losses included in accumulated other comprehensive income
Amount of other-than-temporary impairment losses included in accumulated other comprehensive income for fixed income securities, not included in earnings	$ (5)	$ (12)