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	$ 763	$ 1,726	$ 1,312
Unrealized investment gains (losses) during the year	5,247	(3,057)	2,036
Unrealized investment gains (losses) relating to: Future policy benefits	(1,806)	1,740	(1,824)
Unrealized investment gains (losses) relating to: DAC, VOBA and DSI	(251)	177	(51)
Unrealized investment gains (losses) relating to: Deferred income tax benefit (expense)	(670)	256	253
Unrealized investment gains (losses), end of year	3,283	763	1,726
Change in net unrealized investment gains (losses)	2,520	(884)	414
Restatement Adjustment
Unrealized investment gains (losses), beginning of year	763	1,647	1,312
Unrealized investment gains (losses), end of year		763	1,647
Change Due To Cumulative Effect, Net of Income Tax
Change in net unrealized investment gains (losses)	$ 0	$ (79)	$ 0