Investments- Other-than-temporary losses included in AOCI (Details 7) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Investments [Abstract]
Net unrealized gains related to changes in valuation of fixed income securities subsequent to impairment measurement date	$ 121	$ 131
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	(64)	(71)
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)
Corporate
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	(3)	(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	(8)	(11)
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	(40)	(43)
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	$ (8)	$ (7)