Investments (Net investment income summary) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investment income on fixed maturities	$ 1,353	$ 1,349	$ 1,368
Net realized gains	10	46	6
Affordable housing partnerships	(58)	(100)	(44)
Other	154	108	91
Consolidated investment entities	137	106	155
Total net investment income	$ 1,596	$ 1,509	$ 1,576