Investments (Net investment income summary) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Investment income on fixed maturities	$ 1,403	$ 1,479	$ 1,575
Net realized gains	4	37	7
Affordable housing partnerships	(18)	(25)	(12)
Other	68	93	99
Consolidated investment entities	231	157	220
Total net investment income	$ 1,688	$ 1,741	$ 1,889