Other Financial Data - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Provision	$ 6	$ 9
Accounts written off, net of recoveries	(4)	(8)
Foreign currency translation and other	1	3
Balance at end of period	101	81
Cumulative adjustment amount to decrease retained earnings	(4,361)	(3,260)	$ (3,583)	$ (3,443)
Retained Earnings
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Cumulative adjustment amount to decrease retained earnings	(1,801)	(1,455)	$ (1,042)	$ (1,248)
Cumulative Effect, Period Of Adoption, Adjusted Balance
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 98	$ 77