Supplemental Disclosures (Schedule of Analysis for Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 140	$ 112	$ 110
Provision charged to operations	47	32	34
Accounts written-off, net of recoveries	(30)	(16)	(24)
Effect of exchange rate changes and other	(15)	12	(8)
Balance at end of year	$ 142	$ 140	$ 112