Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 336	$ 144	$ 897	$ 676
Changes in:
Net unrealized gains on investments with other-than-temporary impairments	(1)	1	(11)	(3)
Net unrealized gains on other investments	(158)	23	(746)	167
Net unrealized gains on investments	(159)	24	(757)	164
Foreign currency translation adjustment	0	41	(40)	94
Pension and postretirement benefits	7	10	24	22
Other comprehensive (loss) income, net of tax	(152)	75	(773)	280
Total comprehensive income	$ 184	$ 219	$ 124	$ 956

Unrealized change in value of total investments, after tax.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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