Retirement Plans and Other Retiree Benefits - Summary of Defined Benefit and Other Retiree Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Amounts Recognized in Balance Sheet
Current liabilities	$ (81)	$ (80)
Other Retiree Benefit Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	923	862
Service cost	13	13	$ 14
Interest cost	40	43	44
Participants’ contributions	0	0
Acquisitions/plan amendments	0	0
Actuarial loss (gain)	21	39
Foreign exchange impact	3	1
Termination benefits	(3)	1
Curtailments and settlements	0	0
Benefit payments	(37)	(36)
Other	0	0
Benefit obligations at end of year	960	923	862
Change in Plan Assets
Fair value of plan assets at beginning of year	0	14
Actual return on plan assets	0	1
Company contributions	37	21
Participants’ contributions	0	0
Foreign exchange impact	0	0
Settlements and acquisitions	0	0
Benefit payments	(37)	(36)
Other	0	0
Fair value of plan assets at end of year	0	0	14
Funded Status
Benefit obligations at end of year	960	923	862
Fair value of plan assets at end of year	0	0	14
Net amount recognized	(960)	(923)
Amounts Recognized in Balance Sheet
Noncurrent assets	0	0
Current liabilities	(44)	(44)
Noncurrent liabilities	(916)	(879)
Net amount recognized	(960)	(923)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	338	330
Transition/prior service cost	(1)	(2)
Amounts recognized in accumulated other comprehensive income	337	328
Accumulated benefit obligation	$ 0	$ 0
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	3.80%	4.41%
Long-term rate of return on plan assets		6.80%
Long-term rate of compensation increase	3.50%	0.00%
ESOP growth rate	10.00%	10.00%
Medical cost trend rate of increase	6.00%	6.33%
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	2023
United States | Pension Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	$ 2,298	$ 2,201
Service cost	1	1	2
Interest cost	94	105	100
Participants’ contributions	0	0
Acquisitions/plan amendments	0	0
Actuarial loss (gain)	110	129
Foreign exchange impact	0	0
Termination benefits	24	3
Curtailments and settlements	0	0
Benefit payments	(164)	(141)
Other	0	0
Benefit obligations at end of year	2,363	2,298	2,201
Change in Plan Assets
Fair value of plan assets at beginning of year	1,646	1,624
Actual return on plan assets	225	88
Company contributions	105	75
Participants’ contributions	0	0
Foreign exchange impact	0	0
Settlements and acquisitions	0	0
Benefit payments	(164)	(141)
Other	0	0
Fair value of plan assets at end of year	1,812	1,646	1,624
Funded Status
Benefit obligations at end of year	2,363	2,298	2,201
Fair value of plan assets at end of year	1,812	1,646	1,624
Net amount recognized	(551)	(652)
Amounts Recognized in Balance Sheet
Noncurrent assets	0	0
Current liabilities	(24)	(24)
Noncurrent liabilities	(527)	(628)
Net amount recognized	(551)	(652)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	911	962
Transition/prior service cost	1	2
Amounts recognized in accumulated other comprehensive income	912	964
Accumulated benefit obligation	$ 2,293	$ 2,230
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	3.73%	4.27%
Long-term rate of return on plan assets	6.60%	6.80%
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	14.00%
Average annual rates of return for the most recent 5-year period	8.00%
Average annual rates of return for the most recent 10-year period	6.00%
Average annual rates of return for the most recent 15-year period	8.00%
Average annual rates of return for the most recent 25-year period	8.00%
International | Pension Plans
Change in Benefit Obligations
Benefit obligations at beginning of year	$ 800	$ 802
Service cost	16	16	20
Interest cost	22	25	28
Participants’ contributions	2	2
Acquisitions/plan amendments	(6)	1
Actuarial loss (gain)	(11)	76
Foreign exchange impact	72	(47)
Termination benefits	0	0
Curtailments and settlements	(11)	(37)
Benefit payments	(36)	(36)
Other	(1)	(2)
Benefit obligations at end of year	847	800	802
Change in Plan Assets
Fair value of plan assets at beginning of year	509	520
Actual return on plan assets	42	46
Company contributions	30	54
Participants’ contributions	2	2
Foreign exchange impact	40	(43)
Settlements and acquisitions	(11)	(33)
Benefit payments	(36)	(36)
Other	(1)	(1)
Fair value of plan assets at end of year	575	509	520
Funded Status
Benefit obligations at end of year	847	800	802
Fair value of plan assets at end of year	575	509	$ 520
Net amount recognized	(272)	(291)
Amounts Recognized in Balance Sheet
Noncurrent assets	22	8
Current liabilities	(13)	(12)
Noncurrent liabilities	(281)	(287)
Net amount recognized	(272)	(291)
Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Actuarial loss	209	254
Transition/prior service cost	1	5
Amounts recognized in accumulated other comprehensive income	210	259
Accumulated benefit obligation	$ 787	$ 739
Weighted-Average Assumptions Used to Determine Benefit Obligations
Discount rate	2.53%	2.59%
Long-term rate of return on plan assets	4.04%	4.14%
Long-term rate of compensation increase	2.79%	2.58%
ESOP growth rate	0.00%	0.00%
Medical cost trend rate of increase	0.00%	0.00%