Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	$ 21	$ 13	$ 72
OTTI losses recognized in earnings	21	14	81
Corporate and other bonds
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	12	12	59
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	9	1	13
Equity securities
Debt Securities, Available-for-sale [Line Items]
OTTI losses recognized in earnings	$ 0	$ 1	$ 9