Share-Based Compensation (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based compensation disclosures
Share Based Compensation expense	$ 37,200,000	$ 53,300,000	$ 18,300,000
Options
Issuance of common shares for stock options exercised (in shares)	(3,000,000)	(600,000)	(1,100,000)
Restricted Stock
Share-based compensation disclosures
Share Based Compensation expense	35,000,000	51,100,000	14,100,000
Number of types of performance share awards	2
Option to purchase common stock available for grant	5,000,000
Restricted Stock | Maximum
Share-based compensation disclosures
Vesting period of shares	5 years
Stock options
Share-based compensation disclosures
Option to purchase common stock available for grant	6,300,000	7,800,000
Exercise period	10 years
Assumptions used to value grant date fair value
Weighted-average fair value of options granted (in dollars per share)	$ 6.76	$ 6.05	$ 9.40
Risk free interest rate (as a percent	1.37%	0.79%	0.63%
Dividend yield (as a percent)	1.21%	0.84%	0.00%
Expected volatility (as a percent)	51.01%	51.01%	55.74%
Expected term (in years)	4 years	4 years	4 years
Options
Options outstanding at the beginning of the period (in shares)	18,386,000
Granted (in shares)	61,000
Issuance of common shares for stock options exercised (in shares)	(3,036,000)
Forfeited (in shares)	(4,107,000)
Options outstanding at the end of the period (in shares)	11,304,000	18,386,000
Options exercisable at the end of the period (in shares)	10,955,000
Weighted Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)	$ 21.10
Granted (in dollars per share)	$ 17.93
Exercised (in dollars per share)	$ 9.97
Forfeited (in dollars per share)	$ 23.16
Options outstanding at the end of the period (in dollars per share)	$ 23.30	$ 21.10
Options exercisable at the end of the period (in dollars per share)	$ 23.37
Weighted Average Remaining Contractual Term
Options outstanding at the end of the period	2 years 9 months 22 days
Options exercisable at the end of the period	2 years 8 months 1 day
Aggregate Intrinsic Value
Options outstanding at the end of the period (in dollars)	12,976,000
Options exercisable at the end of the period (in dollars)	$ 12,948,000
Stock options | Employees Executives And Directors
Options
Granted (in shares)	60,662	63,368	658,061
Stock options | Minimum
Share-based compensation disclosures
Vesting period of shares	3 years
Stock options | Maximum
Share-based compensation disclosures
Vesting period of shares	5 years