Investments (Credit Loss Expense Incurred) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Gross credit loss expense recognized in net income (loss)	$ (20)	$ (8)
Net credit loss expense recognized in net income (loss)	(20)	(8)
Corporate Bonds [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Gross credit loss expense recognized in net income (loss)	(20)	(6)
Net credit loss expense recognized in net income (loss)	$ (20)
RMBS [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Gross credit loss expense recognized in net income (loss)		(1)
ABS [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Gross credit loss expense recognized in net income (loss)		$ (1)