Investments (Accrued Investment Income) (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Net Investment Income [Line Items]
Accrued investment income	[1]	$ 3,221	$ 3,330
Fixed maturities
Net Investment Income [Line Items]
Accrued investment income		2,642
Equity securities
Net Investment Income [Line Items]
Accrued investment income		24
Commercial mortgage and other loans
Net Investment Income [Line Items]
Accrued investment income		195
Policy loans
Net Investment Income [Line Items]
Accrued investment income		304
Other invested assets
Net Investment Income [Line Items]
Accrued investment income		37
Short-term investments and cash equivalents
Net Investment Income [Line Items]
Accrued investment income		$ 19

[1] See Note 4 for details of balances associated with variable interest entities.