Debt And Financing Arrangements (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Debt And Financing Arrangements [Line Items]
Excess of fair value over carrying value of long-term debt	$ 1,300,000,000
Maximum amount provided under accounts receivable securitization facility excluded in lines of credit	1,000,000,000
Amount utilized from the securitization facility	1,000,000,000
Convertible senior notes point eight seven five percent due two thousand fourteen [Member]
Debt And Financing Arrangements [Line Items]
Debt instrument face amount	1,150,000,000
Debt instrument, maturity date	Feb. 01, 2014
Lines of credit [Member]
Debt And Financing Arrangements [Line Items]
Lines of credit	8,600,000,000
Unused lines of credit	6,300,000,000
Commercial Paper [Member]
Debt And Financing Arrangements [Line Items]
Lines of credit	6,000,000,000
Borrowing under commercial paper borrowing facility	$ 1,500,000,000