Investments (Net Unrealized Investment Gains (Losses)) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Components of net unrealized investment gains (losses) included in accumulated other comprehensive loss
Fixed maturity securities	$ 11,818	$ 6,894	$ 1,679
Derivatives	162	232	253
Other	(16)	(15)	(15)
Subtotal	11,964	7,111	1,917
Amounts allocated from: Future policy benefits	(4,598)	(2,691)	(885)
Amounts allocated from: DAC, VOBA and DSI	(494)	(332)	(90)
Subtotal	(5,092)	(3,023)	(975)
Deferred income tax benefit (expense)	(1,443)	(859)	(198)
Net unrealized investment gains (losses)	$ 5,429	$ 3,229	$ 744