Restructuring and Related Implementation Charges - Restructuring Activity and Related Accruals (Details) - Global Growth and Efficiency Program - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 146		$ 202
Charges	42	$ 61	71	$ 89
Cash payments	(26)		(50)
Charges against assets	(34)		(46)
Foreign exchange	(1)		(2)
Other	0		(48)
Ending Balance	127		127
Employee-Related Costs
Restructuring Reserve [Roll Forward]
Beginning Balance	52		60
Charges	4		14
Cash payments	(12)		(28)
Charges against assets	(2)		(3)
Foreign exchange	(1)		(2)
Other	0		0
Ending Balance	41		41
Incremental Depreciation
Restructuring Reserve [Roll Forward]
Beginning Balance	0		0
Charges	5		10
Cash payments	0		0
Charges against assets	(5)		(10)
Foreign exchange	0		0
Other	0		0
Ending Balance	0		0
Asset Impairments
Restructuring Reserve [Roll Forward]
Beginning Balance	0		0
Charges	0		6
Cash payments	0		0
Charges against assets	0		(6)
Foreign exchange	0		0
Other	0		0
Ending Balance	0		0
Other
Restructuring Reserve [Roll Forward]
Beginning Balance	94		142
Charges	33		41
Cash payments	(14)		(22)
Charges against assets	(27)		(27)
Foreign exchange	0		0
Other	0		(48)
Ending Balance	$ 86		$ 86