Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Pre-tax
Other comprehensive income (loss)	$ 2,624	$ 855	$ 861	$ 2,082
Tax
Other comprehensive income (loss)	(554)	(180)	(183)	(440)
After-tax
Other comprehensive income (loss)	2,070	675	678	1,642
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	2,796	921	1,363	2,208
Less: reclassification adjustment of realized capital gains and losses	169	57	456	108
Other comprehensive income (loss)	2,627	864	907	2,100
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(590)	(194)	(288)	(467)
Less: reclassification adjustment of realized capital gains and losses	(35)	(12)	(96)	(23)
Other comprehensive income (loss)	(555)	(182)	(192)	(444)
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	2,206	727	1,075	1,741
Less: reclassification adjustment of realized capital gains and losses	134	45	360	85
Other comprehensive income (loss)	2,072	682	715	1,656
Unrealized foreign currency translation adjustments
Pre-tax
Other comprehensive income (loss)	11	5	(38)	11
Tax
Other comprehensive income (loss)	(2)	(1)	8	(2)
After-tax
Other comprehensive income (loss)	9	4	(30)	9
Unamortized pension and other postretirement prior service credit
Pre-tax
Other comprehensive income (loss)	(14)	(14)	(8)	(29)
Tax
Other comprehensive income (loss)	3	3	1	6
After-tax
Other comprehensive income (loss)	$ (11)	$ (11)	$ (7)	$ (23)