Restructuring (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring accrual
Beginning balance, restructuring reserve		$ 45	$ 69
Charges		96	69	$ 92
Write-down of assets to net realizable value		(46)	(17)
Net cash paid, principally severance and related benefits		(37)	(54)	(32)
Transfers to other accounts	$ (14)		(14)
Other, including foreign exchange translation		(13)	(8)
Ending balance, restructuring reserve	45	45	45	69
Restructuring, Additional Information
Settlement cost		(26)	(26)	(74)
Carrying value of impaired assets	0	1	0
Selling and administrative expense
Restructuring accrual
Charges			2
Other income (expense)
Restructuring accrual
Charges			67
Employee Costs
Restructuring accrual
Beginning balance, restructuring reserve		32	47
Charges		40	39
Net cash paid, principally severance and related benefits		(34)	(37)
Transfers to other accounts			(14)
Other, including foreign exchange translation			(3)
Ending balance, restructuring reserve	32	38	32	47
Asset Impairment
Restructuring accrual
Charges		46	17
Write-down of assets to net realizable value		(46)	(17)
Other Exit Costs
Restructuring accrual
Beginning balance, restructuring reserve		13	22
Charges		10	13
Net cash paid, principally severance and related benefits		(3)	(17)
Other, including foreign exchange translation		(13)	(5)
Ending balance, restructuring reserve	$ 13	$ 7	$ 13	$ 22