Debt and Financing Activities (Details) (USD $)	3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2011
Accounts Receivable Securitization Facility [Member]
Line of Credit Facility [Line Items]
Number of years for which accounts receivable sales facility was renewed	1 year
Credit Facility	$ 1,350,000,000
Credit facility expiration date	May 2012
Accounts receivable sold under the facility	0	0
Borrowings outstanding	0		0
Securitized receivable balance	0		0
Line of Credit [Member]
Line of Credit Facility [Line Items]
Credit Facility	1,300,000,000
Credit facility expiration date	June 2012
Borrowings during the period	0	0
Borrowings outstanding	$ 0		$ 0