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	$ 3,229
Unrealized investment gains (losses) during the period	4,470
Unrealized investment gains (losses) relating to: Future policy benefits	(1,940)
Unrealized investment gains (losses) relating to: DAC, VOBA and DSI	(130)
Unrealized investment gains (losses) relating to: Deferred income tax benefit (expense)	(504)
Unrealized investment gains (losses), end of period	5,125
Change in net unrealized investment gains (losses)	$ 1,896