Share-Based Compensation Share-Based Compensation, Textuals (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	44,000,000
Common Stock, Capital Shares Reserved for Future Issuance	11,789,483	4,297,186
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 4,900,000	$ 2,700,000	$ 7,100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	19,857
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	38,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value		22,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 2.73	$ 2.31	$ 0.87
Fair Value of Stock Optins Vested	5,015,000	6,022,000	6,439,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	5,184,000	1,804,000	7,001,000
Proceeds from exercise of stock options	8,227,000	1,759,000	17,407,000
Allocated Share-based Compensation Expense	9,144,000	8,878,000	9,684,000
Stock Options [Member]
Allocated Share-based Compensation Expense	5,100,000	5,300,000	6,500,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	6,600,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1.4
Restricted Stock [Member]
Allocated Share-based Compensation Expense	4,100,000	3,600,000	3,200,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 5,100,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1.3