Investments (Changes in Net Unrealized Investment Gains (Losses)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrealized investment gains (losses), beginning of year	$ 744	$ 1,860	$ 1,277
Unrealized investment gains (losses) during the year	5,194	(2,990)	1,939
Unrealized investment gains (losses) relating to: Future policy benefits	(1,806)	1,485	(1,448)
Unrealized investment gains (losses) relating to: DAC, VOBA and DSI	(242)	172	(67)
Unrealized investment gains (losses) relating to: Deferred income tax benefit (expense)	661	(296)	(159)
Unrealized investment gains (losses), end of year	3,229	744	1,860
Change in net unrealized investment gains (losses)	2,485	(1,037)	583
Restatement Adjustment
Unrealized investment gains (losses), beginning of year	744	1,781	1,277
Unrealized investment gains (losses), end of year		744	1,781
Change Due To Cumulative Effect, Net of Income Tax
Change in net unrealized investment gains (losses)	$ 0	$ (79)	$ 0