Pensions Benefit Plans and Other Postretirement Benefits - Changes in the Benefit Obligation (Details)) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. Pension Plans
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year	$ 1,956	$ 2,190
Change in benefit obligations:
Service cost	14	15	$ 24
Interest cost	78	90	96
Actuarial (gain) loss, including the effect of change in discount rates	123	36
Curtailment, settlement, and plan amendment	(393)	(200)
Benefit payments	(128)	(175)
Net change in benefit obligations	(306)	(234)
Obligations at end of year	1,650	1,956	2,190
Non-U.S. Pension Plans
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year	1,235	1,210
Change in benefit obligations:
Service cost	15	16	15
Interest cost	40	44	44
Actuarial (gain) loss, including the effect of change in discount rates	(15)	160
Curtailment, settlement, and plan amendment	(171)
Participant contributions	1	2
Benefit payments	(60)	(71)
Other		3
Foreign currency translation	103	(129)
Net change in benefit obligations	(87)	25
Obligations at end of year	1,148	1,235	1,210
U.S Postretirement Benefit Plans
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year	92	97
Change in benefit obligations:
Interest cost	4	4	4
Actuarial (gain) loss, including the effect of change in discount rates		(1)
Benefit payments	(7)	(9)
Other		1
Net change in benefit obligations	(3)	(5)
Obligations at end of year	89	92	97
Non-U.S. Postretirement Benefit Plans
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year	81	68
Change in benefit obligations:
Service cost	1	1	1
Interest cost	3	3	3
Actuarial (gain) loss, including the effect of change in discount rates	1	9
Benefit payments	(2)	(2)
Foreign currency translation	5	2
Net change in benefit obligations	8	13
Obligations at end of year	$ 89	$ 81	$ 68