Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
January 1, 2020		$ 22		$ 22
Current-period provision for credit losses				41
Accounts Receivable, Allowance for Credit Loss, Writeoff				15
Foreign currency impact				(1)
September 30, 2020	$ 47			47
Increase in allowance for doubtful accounts related to COVID-19	0	$ 30	$ 0	30	$ 0
Reserve for future COVID-19-related matters	$ 25			$ 25