Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation (Details)

v2.4.0.6
Share-Based Compensation (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
1997 Plan, 2003 Plan and 2011 Plan [Member]
Y
Dec. 31, 2011
1997 Plan, 2003 Plan and 2011 Plan [Member]
Jul. 31, 2012
Cash Awards [Member]
Jul. 31, 2012
Restricted Stock [Member]
Jul. 31, 2012
Restricted Stock [Member]
Issuance of NTP [Member]
Jul. 31, 2012
Restricted Stock [Member]
First Anniversary of NTP [Member]
Jul. 31, 2012
Restricted Stock [Member]
Second Anniversary of NTP [Member]
Jul. 31, 2012
Restricted Stock [Member]
Third Anniversary of NTP [Member]
Jul. 31, 2012
Restricted Stock [Member]
Fourth Anniversary of NTP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Share-Based Compensation Arrangement By Share-Based Payment Award, Value of Cash Awards Authorized             $ 60            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized               10          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Percentage                 35.00% 10.00% 15.00% 15.00% 25.00%
Total share-based compensation expense recognized 49.8 2.3 54.0 16.6                  
Total share-based compensation capitalized     2.2                    
Total unrecognized compensation cost related to non-vested share-based compensation         94.7 7.7              
Recognition period for total unrecognized compensation expense         4                
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition         3.8                
Proceeds from the exercise of stock options   $ 0.8 $ 0.8 $ 0.8