Stock-Based Compensation Outstanding Options and SSARs (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended		3 Months Ended			6 Months Ended	3 Months Ended
	Jun. 30, 2013 years	Dec. 31, 2012	Jun. 30, 2013 Director [Member]	Jun. 30, 2013 Stock Options [Member] Director [Member]	Jun. 30, 2013 Options and SSARs [Member]	Jun. 30, 2013 Options and SSARs [Member]	Jun. 30, 2013 Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Options / SSARs outstanding at January 1, 2012	8,475,000
Incentive shares granted	343,000
Options / SSARs exercised	(1,854,000)
Options / SSARs cancelled	0
Options / SSARs outstanding at September 30, 2012	6,964,000
Options / SSARs outstanding Weighted Average Exercise Price	$ 14.28	$ 12.88
SSARs granted Weighted Average Exercise Price	$ 20.49
Options / SSARs exercised Weighted Average Exercise Price	$ 9.03
Options / SSARs cancelled Weighted Average Exercise Price	$ 0.00
Options / SSARs outstanding Weighted Average Contractual Term (in years)	5.4
Options / SSARs outstanding Aggregate Intrinsic Value (in millions)	$ 25.5
Vested and expected to vest	6,615,000
Vested and expected to vest Aggregate Intrinsic Value (in millions)	24.2
Options / SSARs exercisable	5,711,000
Options / SSARs exercisable Weighted Average Exercise Price	$ 14.74
Options / SSARs exercisable Aggregate Intrinsic Value (in millions)	20.3
Weighted-average period of years costs are expected to be recognied over					1 year 8 months 12 days
Compensation Expense						1.7
Unrecognized compensation costs					$ 5.9	$ 5.9
Vesting Period							3 years
Starting Term When Options Become Exercisable After Grant Date			3 months
Number of Shares Available for Grant					5,600,000	5,600,000
Number of months for options to vest at an incremental rate of ten percent for directors				3 months