Equity Compensation (Stock Options Outstanding by Exercise Price) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 22.65	$ 22.74
$ 13.37 – $15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$ 13.37
Exercise price range, upper limit (in dollars per share)	$ 15.00
$ 15.01 – $25.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$ 15.01
Exercise price range, upper limit (in dollars per share)	$ 25.00
$ 25.01 – $35.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$ 25.01
Exercise price range, upper limit (in dollars per share)	$ 35.00
$ 35.01 – $47.80
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower limit (in dollars per share)	$ 35.01
Exercise price range, upper limit (in dollars per share)	$ 47.80
Stock Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Number Outstanding at end of period (in shares)	3,524,045
Options Outstanding - Weighted Average Remaining Contractual Life	4 years 9 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 22.65
Options Exercisable - Number Exercisable At end of period (in shares)	2,896,375
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 24.20
Stock Options | $ 13.37 – $15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Number Outstanding at end of period (in shares)	931,361
Options Outstanding - Weighted Average Remaining Contractual Life	7 years 7 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 13.91
Options Exercisable - Number Exercisable At end of period (in shares)	400,719
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 13.79
Stock Options | $ 15.01 – $25.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Number Outstanding at end of period (in shares)	1,449,663
Options Outstanding - Weighted Average Remaining Contractual Life	4 years 1 month 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 22.42
Options Exercisable - Number Exercisable At end of period (in shares)	1,353,947
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 22.33
Stock Options | $ 25.01 – $35.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Number Outstanding at end of period (in shares)	837,371
Options Outstanding - Weighted Average Remaining Contractual Life	4 years 3 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 25.74
Options Exercisable - Number Exercisable At end of period (in shares)	836,059
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 25.73
Stock Options | $ 35.01 – $47.80
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding - Number Outstanding at end of period (in shares)	305,650
Options Outstanding - Weighted Average Remaining Contractual Life	0 years 4 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 41.89
Options Exercisable - Number Exercisable At end of period (in shares)	305,650
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 41.89