Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fixed Rate Debt:
Carrying amount - liability	$ 3,005	$ 2,843
Fair value - liability	3,223	2,891
Variable Rate Debt:
Carrying amount - liability	2,778	2,071
Fair value - liability	2,738	2,029
Total Carrying Value in the Consolidated Balance Sheet
Assets:
Investments	44	44
Foreign Exchange Contracts	10	37
Total Assets at Fair Value	54	81
Liabilities:
Foreign Exchange Contracts	13	6
Total Liabilities at Fair Value	13	6
Quoted Prices in Active Markets for Identical Assets/Liabilities, Level 1
Assets:
Investments	44	44
Foreign Exchange Contracts	0	0
Total Assets at Fair Value	44	44
Liabilities:
Foreign Exchange Contracts	0	0
Total Liabilities at Fair Value	0	0
Significant Other Observable Inputs, Level 2
Assets:
Investments	0	0
Foreign Exchange Contracts	10	37
Total Assets at Fair Value	10	37
Liabilities:
Foreign Exchange Contracts	13	5
Total Liabilities at Fair Value	13	5
Significant Unobservable Inputs, Level 3
Assets:
Investments	0	0
Foreign Exchange Contracts	0	0
Total Assets at Fair Value	0	0
Liabilities:
Foreign Exchange Contracts	0	1
Total Liabilities at Fair Value	$ 0	$ 1