Other Financial Data Schedule of Allowance for Doubtful Accounts (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 88	$ 114	$ 90	$ 118
Provision charged to operations	1	(5)	9	6
Accounts written off, net of recoveries	(14)	(8)	(23)	(26)
Effect of exchange rate changes and other	4	(2)	3	1
Balance at end of period	$ 79	$ 99	$ 79	$ 99