Employee Benefit Plans - Share-based Compensation Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	1 Months Ended	12 Months Ended							0 Months Ended	1 Months Ended	12 Months Ended				1 Months Ended	12 Months Ended
	Feb. 09, 2012	Feb. 29, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Time-Based Options [Member] vesting_periods	Dec. 31, 2012 Performance Based Options [Member]	Nov. 29, 2011 Chairman, CEO and President Performance-Based Options [Member]	Jul. 31, 2011 Management Equity Incentive Plan [Member]	Dec. 31, 2012 Management Equity Incentive Plan [Member]	Dec. 31, 2011 Management Equity Incentive Plan [Member]	Dec. 31, 2010 Management Equity Incentive Plan [Member]	Nov. 30, 2011 Management Equity Incentive Plan [Member]	Dec. 31, 2012 2012 Incentive Plan [Member]	Dec. 31, 2012 2012 Incentive Plan [Member]	Dec. 31, 2012 One Subsidiary [Member]	Dec. 31, 2012 One Subsidiary [Member] Liability Classified Awards [Member]	Dec. 31, 2012 One Subsidiary [Member] Equity Classified Awards [Member]	Dec. 31, 2012 Vesting of Performance-Based Options [Member] Performance Based Options [Member]	Dec. 31, 2010 First Vesting Hurdle [Member] Management Equity Incentive Plan [Member]	Dec. 31, 2009 First Vesting Hurdle [Member] Management Equity Incentive Plan [Member]	Jul. 31, 2011 Second Vesting Hurdle [Member] Management Equity Incentive Plan [Member]	Dec. 31, 2010 Second Vesting Hurdle [Member] Management Equity Incentive Plan [Member]	Dec. 31, 2009 Second Vesting Hurdle [Member] Management Equity Incentive Plan [Member]	Dec. 31, 2010 Pro-rata portion of 2.5X options [Member] Management Equity Incentive Plan [Member] Minimum [Member]	Dec. 31, 2010 Pro-rata portion of 2.5X options [Member] Management Equity Incentive Plan [Member] Maximum [Member]	Dec. 31, 2010 Pro-rata portion of 2.5X options increase range [Member] Management Equity Incentive Plan [Member] Minimum [Member]	Dec. 31, 2010 Pro-rata portion of 2.5X options increase range [Member] Management Equity Incentive Plan [Member] Maximum [Member]	Dec. 31, 2012 Majority Stockholders return realized [Member] Management Equity Incentive Plan [Member] Minimum [Member]	Dec. 31, 2012 Majority Stockholders return realized [Member] Management Equity Incentive Plan [Member] Maximum [Member]	Dec. 31, 2012 Sponsors return realized, $35 per share vesting [Member] Performance Based Options [Member]	Dec. 31, 2012 Sponsors return realized, $57.41 per share vesting [Member] Performance Based Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation			$ 55.1	$ 22.2	$ 18.1													$ 20.6	$ 16.8	$ 3.8
Return On Investment										1.00%												1.50%	2.00%	2.00%	2.50%	3.00%	2.00%	2.50%	0.00%	2.50%	1.75%	2.00%	1.50%	2.00%
New vesting schedule on grant-by-grant basis	10 years
Vesting percentage of performace-based options														50.00%
Stock appreciation and options rights granted to individual															4,927,024	3,433,509	3,433,509
Reduced exercise price phased in period						4 years	6 years
Common stock, stock split		1.742
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Stock Options			82.7
Shares issued with respect to incentive stock options																15,449,468	15,449,468
Maximum number of shares of common stock which may be delivered pursuant to performance-based awards																1,373,404	1,373,404
Aggregate amount of compensation to be paid in respect of all performance-based awards																	25.0
Maximum number of shares of the Company's common stock																	6,500,000
Option Exchange exercise price	$ 20.09
Replacement options exercise price			$ 8.22
Eligible option to purchase common stock granted										290,334
Option Exchange, additional expenses			3.0
Additional option exchange expense will be recognized in future period			12.2
Percentage of Replacement Options immediately vested and vested in each of the first four anniversaries								20.00%
Number Of Vested Instalments								4
Number of trailing day of common stock									30 days	30 days
Average common stock closing price per share									$ 35.00	$ 57.41	$ 35										$ 57.41
Additional stock option expense recognized as a result of plan amendments												$ 3.3	$ 3.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition			6 years 9 months 18 days
Restricted Common Stock [Abstract]
Restricted stock issued																50,000
Percentage of restricted stock awards vesting annually on the first and second anniversaries of the grant date																50.00%