Stockholders' Equity Narrative (Details) (USD $)	1 Months Ended			12 Months Ended
	Oct. 31, 2013	Jan. 31, 2013	Apr. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]
Amount of common stock repurchases authorized	$ 750,000,000	$ 150,000,000	$ 150,000,000
Stock repurchase authorized period (in months)		12 months	12 months
Repurchases of common stock (in shares)				3,897,282	4,400,000	12,276,878.000000
Value of shares repurchased during period				160,418,000	141,468,000	324,733,000
Remaining amount available for future purchases of shares under approved repurchase program.				$ 702,300,000