Restructuring Charges, Net and Asset Impairments - Roll Forward of Restructuring Reserve (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	$ 99	$ 100	$ 83	$ 101	$ 100	$ 101
Provisions	32	34	96	15
Revisions to estimates	(8)	(9)	(4)	(2)
Payments	(24)	(25)	(35)	(30)
Foreign currency		(1)		(1)
Restructuring reserve, ending balance	99	99	140	83	99	140
Employee Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	99	99	81	97	99	97
Provisions	30	31	90	10
Revisions to estimates	(8)	(9)	(4)	(2)
Payments	(22)	(21)	(31)	(23)
Foreign currency		(1)		(1)
Restructuring reserve, ending balance	99	99	136	81	99	136
Facility Closure and Other Costs
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance	0	1	2	4	1	4
Provisions	2	3	6	5
Revisions to estimates	0	0	0	0
Payments	(2)	(4)	(4)	(7)
Foreign currency		0		0
Restructuring reserve, ending balance	$ 0	$ 0	$ 4	$ 2	$ 0	$ 4