Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pre-tax
Other comprehensive (loss) income	$ (1,210)	$ 1,033	$ 518
After-tax
Other comprehensive (loss) income	(953)	673	339
Tax
Other comprehensive (loss) income	257	(360)	(179)
Unrealized net capital gains and losses
Pre-tax
Unrealized net holding during the period	(1,142)	866	486
Less: reclassification adjustment	(186)	374	(180)
Other comprehensive (loss) income	(956)	492	666
After-tax
Unrealized net holding during the period	(901)	562	316
Less: reclassification adjustment	(147)	243	(117)
Other comprehensive (loss) income	(754)	319	433
Tax
Unrealized net holding during the period	241	(304)	(170)
Less: reclassification adjustment	39	(131)	63
Other comprehensive (loss) income	202	(173)	(233)
Unrealized foreign currency translation adjustments
Pre-tax
Other comprehensive (loss) income	(70)	72	15
After-tax
Other comprehensive (loss) income	(55)	47	10
Tax
Other comprehensive (loss) income	15	(25)	(5)
Unrecognized pension and other postretirement benefit cost
Pre-tax
Unrealized net holding during the period	(464)	232	(263)
Less: reclassification adjustment	(280)	(237)	(100)
Other comprehensive (loss) income	(184)	469	(163)
After-tax
Unrealized net holding during the period	(365)	153	(169)
Less: reclassification adjustment	(221)	(154)	(65)
Other comprehensive (loss) income	(144)	307	(104)
Tax
Unrealized net holding during the period	99	(79)	94
Less: reclassification adjustment	59	83	35
Other comprehensive (loss) income	$ 40	$ (162)	$ 59

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