Stockholders' Equity (Share Repurchase Program) (Details 1) (USD $)	12 Months Ended			15 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Rate
Stock Repurchase Program, Authorized Amount	$ 771,200,000	$ 500,000,000
Treasury Stock, Shares, Acquired				31,100,000
Treasury Stock Percentage Repurchased				7.70%
Treasury Stock, Value, Acquired, Cost Method	(8,125,000)	(9,683,000)	(6,729,000)	(461,900,000)
Stock Repurchase Program, Remaining Authorized Repurchase Amount	309,300,000
Treasury Stock Repurchase Program [Member]
Treasury Stock, Shares, Acquired	17,000,000	14,100,000
Treasury Stock, Value, Acquired, Cost Method	$ (266,700,000)	$ (195,200,000)
Treasury Stock Acquired, Average Cost Per Share	$ 15.71	$ 13.83