Equity Compensation (Stock Options Outstanding by Exercise Price) (Details) - $ / shares	6 Months Ended
	Jun. 30, 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)	$ 22.85	$ 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)	3,403,390
Options Outstanding - Weighted Average Remaining Contractual Life	4 years 4 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 22.85
Options Exercisable - Number Exercisable At end of period (in shares)	2,911,536
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 24.04
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)	847,361
Options Outstanding - Weighted Average Remaining Contractual Life	7 years 4 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 13.90
Options Exercisable - Number Exercisable At end of period (in shares)	446,936
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 13.91
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)	1,426,858
Options Outstanding - Weighted Average Remaining Contractual Life	3 years 9 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 22.44
Options Exercisable - Number Exercisable At end of period (in shares)	1,336,741
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 22.35
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)	826,721
Options Outstanding - Weighted Average Remaining Contractual Life	4 years 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 25.74
Options Exercisable - Number Exercisable At end of period (in shares)	825,409
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)	302,450
Options Outstanding - Weighted Average Remaining Contractual Life	2 months 13 days
Options Outstanding - Weighted Average Exercise Price (in dollars per share)	$ 41.88
Options Exercisable - Number Exercisable At end of period (in shares)	302,450
Options Exercisable - Weighted Average Exercise Price (in dollars per share)	$ 41.88