Investments (Net Inv Inc summary) (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Investment income on fixed maturities	$ 334	$ 335	$ 663	$ 672
Net realized gains (losses)	5	21	11	38
Affordable housing partnerships	(14)	(13)	(25)	(25)
Other	43	20	89	44
Consolidated investment entities	51	28	77	53
Total	$ 419	$ 391	$ 815	$ 782