Trade Receivables Securitization (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2011	Mar. 31, 2010
Schedule of trade receivable securitization [Line Items]
Percent of receivables sold to unaffiliated institutions			100.00%
Company's accounts receivable sold to third-party	$ 1,400,000,000		$ 1,400,000,000		$ 1,000,000,000
Cash proceeds from sale of accounts receivable	600,700,000		600,700,000		545,000,000
Deferred purchase price receivable	750,315,000	821,239,000	750,315,000	821,239,000	459,994,000	135,401,000
Cash flows from new transfers of receivables			400,000,000	500,000,000
Receivables sold but not yet collected from banking institutions	54,100,000		54,100,000		109,700,000
Accounts receivable sold to certain third party banking institutions			1,600,000,000	1,900,000,000
Cash proceeds from the sale of accounts receivables	3,600,000,000	1,500,000,000	3,600,000,000	1,500,000,000
Recognized loss on sale of the related receivables and recorded in interest and other expense, net	2,500,000	2,400,000	8,800,000	13,100,000
North American Program [Member]
Schedule of trade receivable securitization [Line Items]
Investment limits with financial institution	300,000,000		300,000,000
Global Program [Member]
Schedule of trade receivable securitization [Line Items]
Investment limits with financial institution	500,000,000		500,000,000
Accounts receivable sold to commercial paper conduit						$ 217,100,000