Stockholders' Equity (Details Textual) (USD $) Share data in Millions, unless otherwise specified	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Stockholders' Equity (Textual) [Abstract]
Weighted average potential anti-dilutive common shares excluded from the calculation of diluted EPS		4.9	0.4	1.8	3.2
Amount authorized by Board of Directors to repurchase common stock				$ 4,000,000,000
Treasury stock, shares repurchased		6.3		15.1
Treasury Stock acquired, Value		225,000,000		630,500,000
Remaining authorized amount in stock repurchase program				1,000,000,000
Number of shares repurchased to satisfy employee tax withholding obligations		0.2		0.6
Amount paid for shares repurchased to satisfy employee tax withholding obligations		8,700,000		31,700,000
Additional amount authorized by the Board of Directors to repurchase common stock	$ 1,000,000,000