Stock-Based Compensation Stock Based Compensation (RSU) Details 2 (Details) - 6 months ended Jun. 30, 2015 - $ / shares
Total
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]  
RSUs granted 2,041,106
Restricted Stock Units (RSUs) [Member]  
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]  
RSU Shares Outstanding, Beginning of Period 2,818,661
RSUs granted 2,041,106
RSUs vested (357,242)
RSUs forfeited (79,987)
RSU Shares Outstanding, End of Period 4,422,538
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Weighted Average Exercise Price [Roll Forward]  
Weighted Average Fair Value, Beginning of Period, USD per share $ 77.77
Weighted Average Fair Value, RSUs granted, USD per share 102.12
Weighted Average Fair Value, RSUs vested, USD per share 82.42
Weighted Average Fair Value, RSUs forfeited, USD per share 82.48
Weighted Average Fair Value, End of Period, USD per share $ 88.54