Stock-Based Compensation (Net Tax Windfall) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2012
Balance at December 31, 2012
|
Dec. 31, 2013
Net Windfall Resulting From Exercises and Conversions
|
Dec. 31, 2013
Balance at December 31, 2013
|
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Accumulated tax windfall in additional contributed capital | $ 36.2 | $ 5.7 | $ 41.9 |