Trade Receivables (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in allowances for uncollectible accounts
Beginning balance	$ (65)	$ (65)	$ (70)
Provision charged to expense	(3)	(11)	(5)
Write-offs, net of recoveries	14	14	10
Acquisitions and divestitures	(1)	0	(4)
Foreign currency translation	1	(1)	2
Transfer to assets held for sale	8	0	0
Other	0	(2)	2
Ending balance	$ (46)	$ (65)	$ (65)