Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Pre-tax
Other comprehensive (loss) income	$ (1,763)	$ 1,227
Tax
Other comprehensive (loss) income	371	(260)
After-tax
Other comprehensive (loss) income	(1,392)	967
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	(1,433)	1,287
Less: reclassification adjustment of realized capital gains and losses	287	51
Other comprehensive (loss) income	(1,720)	1,236
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets	303	(273)
Less: reclassification adjustment of realized capital gains and losses	(60)	(11)
Other comprehensive (loss) income	363	(262)
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets	(1,130)	1,014
Less: reclassification adjustment of realized capital gains and losses	227	40
Other comprehensive (loss) income	(1,357)	974
Unrealized foreign currency translation adjustments
Pre-tax
Other comprehensive (loss) income	(49)	6
Tax
Other comprehensive (loss) income	10	(1)
After-tax
Other comprehensive (loss) income	(39)	5
Unamortized pension and other postretirement prior service credit
Pre-tax
Other comprehensive (loss) income	6	(15)
Tax
Other comprehensive (loss) income	(2)	3
After-tax
Other comprehensive (loss) income	$ 4	$ (12)

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