Retirement Plans and Other Retiree Benefits - Summary of Defined Benefit and Other Retiree Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amounts Recognized in Balance Sheet
Current liabilities	$ (84)	$ (81)
Other Retiree Benefit Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	960	923
Service cost	16	13	$ 13
Interest cost	38	40	43
Participants’ contributions	0	0
Acquisitions/plan amendments	0	0
Actuarial loss (gain)	(88)	21
Foreign exchange impact	(5)	3
Termination benefits	0	(3)
Curtailments and settlements	0	0
Benefit payments	(45)	(37)
Other	0	0
Benefit obligations at end of year	876	960	923
Change in Plan Assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	(1)	0
Company contributions	100	37
Participants’ contributions	0	0
Foreign exchange impact	0	0
Settlements and acquisitions	0	0
Benefit payments	(45)	(37)
Other	0	0
Fair value of plan assets at end of year	54	0	0
Funded Status
Benefit obligations at end of year	876	960	923
Fair value of plan assets at end of year	54	0	0
Net amount recognized	(822)	(960)
Amounts Recognized in Balance Sheet
Noncurrent assets	0	0
Current liabilities	(46)	(44)
Noncurrent liabilities	(776)	(916)
Net amount recognized	(822)	(960)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	239	338
Transition/prior service cost	(1)	(1)
Amounts recognized in accumulated other comprehensive income	238	337
Accumulated benefit obligation	$ 0	$ 0
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	4.43%	3.80%
Long-term rate of return on plan assets		6.60%
Long-term rate of compensation increase	3.50%	3.50%
ESOP growth rate	10.00%	10.00%
Medical cost trend rate of increase	6.00%	6.00%
Assumed medical cost trend rates [Abstract]
Medical cost trend rate assumed for next fiscal year	6.00%
Ultimate medical cost trend rate	4.75%
Year which ultimate medical cost trend rate is reached	2024
United States | Pension Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	$ 2,363	$ 2,298
Service cost	1	1	1
Interest cost	86	94	105
Participants’ contributions	0	0
Acquisitions/plan amendments	0	0
Actuarial loss (gain)	(139)	110
Foreign exchange impact	0	0
Termination benefits	9	24
Curtailments and settlements	(4)	0
Benefit payments	(169)	(164)
Other	0	0
Benefit obligations at end of year	2,147	2,363	2,298
Change in Plan Assets
Fair value of plan assets at beginning of year	1,812	1,646
Actual return on plan assets	(101)	225
Company contributions	30	105
Participants’ contributions	0	0
Foreign exchange impact	0	0
Settlements and acquisitions	(4)	0
Benefit payments	(169)	(164)
Other	0	0
Fair value of plan assets at end of year	1,568	1,812	1,646
Funded Status
Benefit obligations at end of year	2,147	2,363	2,298
Fair value of plan assets at end of year	1,568	1,812	1,646
Net amount recognized	(579)	(551)
Amounts Recognized in Balance Sheet
Noncurrent assets	0	0
Current liabilities	(26)	(24)
Noncurrent liabilities	(553)	(527)
Net amount recognized	(579)	(551)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	940	911
Transition/prior service cost	1	1
Amounts recognized in accumulated other comprehensive income	941	912
Accumulated benefit obligation	$ 2,090	$ 2,293
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	4.38%	3.73%
Long-term rate of return on plan assets	6.60%	6.60%
Long-term rate of compensation increase	3.50%	3.50%
ESOP growth rate	0.00%	0.00%
Medical cost trend rate of increase	0.00%	0.00%
Long-term rate of return on plan assets [Abstract]
Average annual rates of return for the most recent 1-year period	(5.00%)
Average annual rates of return for the most recent 5-year period	5.00%
Average annual rates of return for the most recent 10-year period	8.00%
Average annual rates of return for the most recent 15-year period	6.00%
Average annual rates of return for the most recent 25-year period	7.00%
International | Pension Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	$ 847	$ 800
Service cost	14	16	16
Interest cost	21	22	25
Participants’ contributions	2	2
Acquisitions/plan amendments	4	(6)
Actuarial loss (gain)	(11)	(11)
Foreign exchange impact	(40)	72
Termination benefits	0	0
Curtailments and settlements	(7)	(11)
Benefit payments	(42)	(36)
Other	(1)	(1)
Benefit obligations at end of year	787	847	800
Change in Plan Assets
Fair value of plan assets at beginning of year	575	509
Actual return on plan assets	(16)	42
Company contributions	27	30
Participants’ contributions	3	2
Foreign exchange impact	(29)	40
Settlements and acquisitions	(7)	(11)
Benefit payments	(42)	(36)
Other	(1)	(1)
Fair value of plan assets at end of year	510	575	509
Funded Status
Benefit obligations at end of year	787	847	800
Fair value of plan assets at end of year	510	575	$ 509
Net amount recognized	(277)	(272)
Amounts Recognized in Balance Sheet
Noncurrent assets	6	22
Current liabilities	(12)	(13)
Noncurrent liabilities	(271)	(281)
Net amount recognized	(277)	(272)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	226	209
Transition/prior service cost	6	1
Amounts recognized in accumulated other comprehensive income	232	210
Accumulated benefit obligation	$ 731	$ 787
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	2.80%	2.53%
Long-term rate of return on plan assets	4.06%	4.04%
Long-term rate of compensation increase	2.86%	2.79%
ESOP growth rate	0.00%	0.00%
Medical cost trend rate of increase	0.00%	0.00%