Investments (Realized Investment Gains Losses, Net) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	$ 1,667	$ (766)
Fixed maturities
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	158	260
Commercial mortgage and other loans
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	22	10
Investment real estate
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	(1)	0
LPs/LLCs
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	(3)	(5)
Derivatives
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	1,492	(1,032)
Other
Gain (Loss) on Securities [Line Items]
Realized investment gains (losses), net	$ (1)	$ 1