Pension and Postretirement Benefit Plans - Reconciliations of Changes in Benefit Obligations, Plan Assets and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Reconciliation of fair value of plan assets [Roll Forward]:
Fair value at beginning of period	$ 1,584
Fair value at end of period	1,372	$ 1,584
Pension Plan [Member] \| UNITED STATES
Reconciliation of benefit obligation [Roll Forward]:
Obligation at beginning of period	1,730	1,682
Interest cost	43	51	$ 53
Service cost
Actuarial (gain) loss	(148)	115
Benefit payments	(124)	(118)
Settlements
Translation adjustments
Obligation at end of period	1,501	1,730	1,682
Reconciliation of fair value of plan assets [Roll Forward]:
Fair value at beginning of period	1,513	1,454
Actual return on plan assets	(88)	175
Employer contributions		2
Benefit payments	(124)	(118)
Settlements
Translation adjustments
Fair value at end of period	1,301	1,513	1,454
Funded status at end of period	(200)	(217)
Pension Plan [Member] \| Foreign Plan [Member]
Reconciliation of benefit obligation [Roll Forward]:
Obligation at beginning of period	377	309
Interest cost	7	7	7
Service cost	7	7	5
Actuarial (gain) loss	7	7
Benefit payments	(14)	(14)
Acquisitions		22
Settlements	(2)	(1)
Termination benefit		1
Curtailment		(1)
Translation adjustments	(18)	40
Obligation at end of period	364	377	309
Reconciliation of fair value of plan assets [Roll Forward]:
Fair value at beginning of period	71	51
Actual return on plan assets	6	6
Employer contributions	16	15
Benefit payments	(14)	(14)
Settlements	(2)	(1)
Acquisition		12
Translation adjustments	(6)	2
Fair value at end of period	71	71	51
Funded status at end of period	(293)	(306)
Other Postretirement Benefits Plan [Member] \| Foreign Plan [Member]
Reconciliation of benefit obligation [Roll Forward]:
Obligation at beginning of period	99	91
Interest cost	3	3	3
Service cost	1	1	1
Actuarial (gain) loss	(7)	2
Benefit payments	(5)	(5)
Settlements
Translation adjustments	(8)	7
Obligation at end of period	83	99	91
Reconciliation of fair value of plan assets [Roll Forward]:
Fair value at beginning of period	0	0
Actual return on plan assets
Employer contributions	5	5
Benefit payments	(5)	(5)
Settlements
Translation adjustments
Fair value at end of period	0	0	$ 0
Funded status at end of period	$ (83)	$ (99)

Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of increase in benefit obligation of defined benefit plan from business combination.

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Amount of increase in plan assets of defined benefit plan from business combination.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of (increase) decrease in benefit obligation of defined benefit plan from event reducing expected years of future service of present employees or eliminating accrual of benefits for some or all future services of present employees.

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Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Amount of foreign currency translation gain (loss) which (increases) decreases benefit obligation of defined benefit plan.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of cost recognized for passage of time related to defined benefit plan.

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Amount of payment to participant under defined benefit plan which decreases plan assets. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Amount of foreign currency translation gain (loss) which increases (decreases) plan assets of defined benefit plan.

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Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement.

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Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract.

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Amount of increase in benefit obligation for benefits provided to employees payable from defined benefit plan or payable upon retirement.

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