Stock-Based Compensation Outstanding Options and SSARs (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 years	Dec. 31, 2012
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	(1,805,000)
Options / SSARs cancelled	0
Options / SSARs outstanding at September 30, 2012	7,013,000
Options / SSARs outstanding Weighted Average Exercise Price	$ 14.22	$ 12.88
SSARs granted Weighted Average Exercise Price	$ 20.49
Options / SSARs exercised Weighted Average Exercise Price	$ 9.13
Options / SSARs cancelled Weighted Average Exercise Price	$ 0.00
Options / SSARs outstanding Weighted Average Contractual Term (in years)	5.7
Options / SSARs outstanding Aggregate Intrinsic Value (in millions)	$ 57.4
Vested and expected to vest	6,663,000
Vested and expected to vest Aggregate Intrinsic Value (in millions)	54.6
Options / SSARs exercisable	5,719,000
Options / SSARs exercisable Weighted Average Exercise Price	$ 14.70
Options / SSARs exercisable Aggregate Intrinsic Value (in millions)	45.2
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Starting Term When Options Become Exercisable After Grant Date	3 months
Stock Options [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of months for options to vest at an incremental rate of ten percent for directors	3 months
Options and SSARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Weighted-average period of years costs are expected to be recognied over	1 year 10 months 24 days
Compensation Expense	0.8
Unrecognized compensation costs	$ 6.8
Number of Shares Available for Grant	4,300,000
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]
Vesting Period	3 years