DAC, VOBA, DSI, and DFEL (DAC) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in DAC [Roll Forward]
Balance as of beginning-of-year	$ 9,509	$ 7,909	$ 8,269
Business acquired (sold) through reinsurance		(246)
Business recaptured through reinsurance	59
Deferrals	1,900	1,596	1,345
Amortization, net of interest:
Amortization, excluding unlocking, net of interest	(922)	(913)	(922)
Unlocking	(471)	(115)	61
Adjustment related to realized gains (losses)	(43)	(42)	(55)
Adjustment related to unrealized (gains) losses	(2,614)	1,320	(789)
Balance as of end-of-year	$ 7,418	$ 9,509	$ 7,909