Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pre-tax
Other comprehensive income (loss)	$ 261	$ 440	$ 1,122	$ 2,522
Tax
Other comprehensive income (loss)	(56)	(93)	(239)	(533)
After-tax
Other comprehensive income (loss)	205	347	883	1,989
Unrealized net holding gains and losses arising during the period, net of related offsets
Pre-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	414	603	1,777	2,811
Less: reclassification adjustment of realized capital gains and losses	233	136	689	244
Other comprehensive income (loss)	181	467	1,088	2,567
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(88)	(127)	(376)	(593)
Less: reclassification adjustment of realized capital gains and losses	(49)	(29)	(145)	(51)
Other comprehensive income (loss)	(39)	(98)	(231)	(542)
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	326	476	1,401	2,218
Less: reclassification adjustment of realized capital gains and losses	184	107	544	193
Other comprehensive income (loss)	142	369	857	2,025
Unrealized foreign currency translation adjustments
Pre-tax
Other comprehensive income (loss)	32	(12)	(6)	(1)
Tax
Other comprehensive income (loss)	(7)	2	1	0
After-tax
Other comprehensive income (loss)	25	(10)	(5)	(1)
Unamortized pension and other postretirement prior service credit
Pre-tax
Other comprehensive income (loss)	48	(15)	40	(44)
Tax
Other comprehensive income (loss)	(10)	3	(9)	9
After-tax
Other comprehensive income (loss)	$ 38	$ (12)	$ 31	$ (35)