Stockholders' Equity (Details Textuals) (USD $) Share data in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2011	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Stockholders' Equity (Textuals) [Abstract]
Weighted average potential anti-dilutive common shares excluded from the calculation of diluted EPS		1.5	3.6	0.9	3.7
Amount authorized by Board of Directors to repurchase common stock				$ 4,000,000,000
Treasury stock, shares repurchased		5.4		8.8
Treasury Stock acquired, Value		225,000,000		405,500,000
Remaining authorized amount in stock repurchase program				225,300,000
Number of shares repurchased to satisfy employee tax withholding obligations				0.4
Amount paid for shares repurchased to satisfy employee tax withholding obligations		1,300,000		23,000,000
Additional amount authorized by the Board of Directors to repurchase common stock	$ 1,000,000,000