Investments (Changes in Net Unrealized Investment Gains (Losses)) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Investments, Debt and Equity Securities [Abstract]
Unrealized investment gains (losses), beginning of period	$ 3,283
Unrealized investment gains (losses) during the period	4,539
Unrealized investment gains (losses) relating to: Future policy benefits	(1,684)
Unrealized investment gains (losses) relating to: DAC, VOBA and DSI	(141)
Unrealized investment gains (losses) relating to: Deferred income tax benefit (expense)	(570)
Unrealized investment gains (losses), end of period	5,427
Change in net unrealized investment gains (losses)	$ 2,144