Allowance For Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 117	$ 109	$ 77
Provision charged to expense	20	18	32
Accounts written off	(32)	(12)	(10)
Acquisitions, currency translation and other	(3)	2	10
Ending Balance	$ 102	$ 117	$ 109