Share-Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Share-based compensation disclosures
Share Based Compensation expense	$ 8,600,000	$ 6,000,000	$ 19,300,000	$ 38,800,000
Liability related to awards	153,783,000		153,783,000		172,803,000
Restricted Stock Award | Employees and Director
Share-based compensation disclosures
Shares awarded during period			1,143,002	4,334,581
Aggregate value of restricted stock awards at date of grant	26,100,000	71,100,000	26,100,000	71,100,000
Fair value awards vested			25,300,000	36,300,000
Restricted Stock Award | Maximum | Employees and Director
Share-based compensation disclosures
Vesting period of shares			4 years
Restricted Stock Based on Performance Conditions | Executives
Share-based compensation disclosures
Shares awarded during period			362,311
Vesting period of shares			3 years
Liability related to awards	1,000,000		1,000,000
Restricted Stock Based on Market Conditions
Assumptions used to value grant date fair value
Risk free interest rate (as a percent)			0.80%	0.41%
Expected volatility (as a percent)			40.00%	46.00%
Closing stock price (in dollars per share)	$ 18.19	$ 16.53	$ 18.19	$ 16.53
Expected term (in years)			2 years 11 months 19 days	2 years 9 months 25 days
Restricted Stock Based on Market Conditions | Executives
Share-based compensation disclosures
Shares awarded during period			395,550	353,933
Vesting period of shares			3 years
Aggregate value of restricted stock awards at date of grant	4,500,000	3,700,000	4,500,000	3,700,000
Stock options | Employees and Director
Share-based compensation disclosures
Total intrinsic value of stock options exercised			46,900,000	2,400,000
Total fair value of option vested during the period			$ 1,500,000	$ 3,900,000