Valuation and Qualifying Accounts (Allowance for Doubtful Accounts) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance at Beginning of Period	$ 58	$ 56	$ 57
Charged to Costs & Expenses	21	10	9
Uncollectible amounts written off, net of recoveries	11	8	9
Effect of changes in foreign exchange rates	(4)	0	1
Balance at End of Period	$ 72	$ 58	$ 56