Reclassifications From Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Reclassifications from accumulated other comprehensive (loss) income
Reclassification of disproportionate tax effects		$ 0
Actuarial losses, net
Reclassifications from accumulated other comprehensive (loss) income
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	$ 5	5
Reclassification from AOCI, Current Period, Tax	(1)	0
Reclassifications, after tax	$ 4	5
Accounting Standards Update 2018-02
Reclassifications from accumulated other comprehensive (loss) income
Reclassification of disproportionate tax effects		$ 59

Tax Cuts And Jobs Act Of 2017, Reclassification from Aoci To Retained Earnings, Tax Effect

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Amount before tax of reclassification adjustments of other comprehensive income (loss).

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