Other Financial Data - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at January 1	$ 58	$ 74	$ 90
Provision charged to operations	11	13	12
Accounts written off, net of recoveries	(14)	(34)	(33)
Foreign currency translation	3	5	5
Balance at December 31	$ 58	$ 58	$ 74