Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	$ 44	$ 21	$ 13
OTTI losses recognized in earnings	44	21	14
Corporate and other bonds
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	33	12	12
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Total fixed maturity securities available-for-sale	11	9	1
Equity securities
Debt Securities, Available-for-sale [Line Items]
OTTI losses recognized in earnings	$ 0	$ 0	$ 1