Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pre-tax
Other comprehensive income (loss)	$ 1,720	$ 2,322	$ (1,094)
Tax
Other comprehensive income (loss)	(366)	(490)	233
After-tax
Other comprehensive income (loss)	1,354	1,832	(861)
Unrealized net capital gains and losses
Pre-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	2,512	2,807	(1,142)
Less: reclassification adjustment of realized capital gains and losses	870	413	(186)
Other comprehensive income (loss)	1,642	2,394	(956)
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(532)	(592)	241
Less: reclassification adjustment of realized capital gains and losses	(183)	(87)	39
Other comprehensive income (loss)	(349)	(505)	202
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	1,980	2,215	(901)
Less: reclassification adjustment of realized capital gains and losses	687	326	(147)
Other comprehensive income (loss)	1,293	1,889	(754)
Unrealized foreign currency translation adjustments
Pre-tax
Other comprehensive income (loss)	66	(13)	(61)
Tax
Other comprehensive income (loss)	(14)	3	13
After-tax
Other comprehensive income (loss)	52	(10)	(48)
Unamortized pension and other postretirement prior service credit
Pre-tax
Other comprehensive income (loss)	12	(59)	(77)
Tax
Other comprehensive income (loss)	(3)	12	18
After-tax
Other comprehensive income (loss)	$ 9	$ (47)	$ (59)