Restructuring of Operations - Accrued Restructuring Costs and Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning balance	$ 38	$ 17	$ 21
Charges to restructuring	22	38	15
Adjustments of accruals	(8)	(2)
Cash payments	(28)	(15)	(16)
Currency impact	2		(3)
Ending Balance	26	38	17
Employee Termination Benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	32	9	12
Charges to restructuring	16	35	12
Adjustments of accruals	(8)	(2)
Cash payments	(21)	(10)	(12)
Currency impact	2		(3)
Ending Balance	21	32	9
Exit Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	6	8	9
Charges to restructuring	6	3	3
Adjustments of accruals
Cash payments	(7)	(5)	(4)
Currency impact
Ending Balance	$ 5	$ 6	$ 8