Investments Investments (ACL for Fixed Maturity Securities AFS By Sector) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Amortized cost of fixed maturity securities valuation allowances	$ (187)	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	(187)
U.S. corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Amortized cost of fixed maturity securities valuation allowances	(51)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	(51)
Foreign government
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Amortized cost of fixed maturity securities valuation allowances	(136)	$ 0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not Previously Recorded	$ (136)