Other Financial Data Schedule of Allowance for Doubtful Accounts (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period	$ 90	$ 118
Provision charged to operations	4	10
Accounts written off, net of recoveries	(5)	(9)
Effect of exchange rate changes and other	0	3
Balance at end of period	$ 89	$ 122