Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Comprehensive Income (Loss):
Foreign currency translation, tax	$ (1)	$ 0	$ 4	$ (8)	$ 3	$ (8)
Defined benefit plans:
Amortization of prior service cost and unrecognized gains and (losses) included in total benefit cost, tax	8	8	16	16	24	24
(Increase)/Decrease in net actuarial losses, tax	(3)	(4)	4	6	1	2
Immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures, tax	0	2		2	0	4
Prior service (cost) credit from plan amendments, tax	0	0	0		0	0
Deferred derivative gains (losses), tax	4	1	0	2	4	3
Reclassification adjustment for amounts recognized in income, tax	$ 0	$ 0	$ (1)	$ 2	$ (1)	$ 2

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Amount of tax expense (benefit) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount of tax expense (benefit) for increase (decrease) to other comprehensive income from settlement and curtailment gain (loss) of defined benefit plan.

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Amount of tax expense (benefit), before reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount of tax (expense) benefit of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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