Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Liabilities
Book/tax basis difference due to depreciation	$ 806.7	$ 756.2
Leveraged leases	0	62.7
Investments in affiliated companies	81.6	82.4
Lease accounting (other than leveraged)	12.6	13.7
Other	3.1	2.9
Total deferred tax liabilities	904.0	917.9
Deferred Tax Assets
Alternative minimum tax credit	5.2	8.9
Federal net operating loss	0	38.1
Foreign tax credit	7.3	13.9
Valuation on foreign tax credit	(7.3)	(13.9)
State net operating loss	26.6	31.1
Valuation on state net operating loss	(12.8)	(15.8)
Foreign net operating loss	9.5	7.3
Accruals not currently deductible for tax purposes	19.1	21.8
Allowance for losses	6.6	5.4
Pension and post-retirement benefits	48.6	40.7
Other	18.2	14.5
Total deferred tax assets	121.0	152.0
Net deferred tax liabilities	783.0	765.9
Gross liability for unrecognized tax benefits
Beginning balance	20.8	42.7
Reductions due to expiration of the applicable statute of limitations	(16.1)	0
Reductions due to settlement of audit issues	0	21.9
Ending balance	$ 4.7	$ 20.8