Investments (Components of Net Investment Gains (Losses)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Net investment gains (losses), fixed maturity securities	$ 87	$ (178)	$ (26)
Net investment gains (losses), equity securities	17	(16)	22
Net investment gains (losses), mortgage loans	(10)	(13)	(9)
Net investment gains (losses), limited partnerships and LLCs	7	40	(7)
Net investment gains (losses), other	(9)	(37)	(7)
Net investment gains (losses)	$ 92	$ (204)	$ (27)