Debt (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Instrument	Dec. 31, 2014 USD ($) Instrument	Dec. 31, 2013 USD ($)
Line of Credit Facility [Line Items]
Non-Recourse Debt	$ 6.9	$ 15.9
Operating assets pledged as collateral for notes	83.2
Other Short-term Borrowings	7.4	72.1
Annual commitment fees	$ 1.0	$ 1.0	$ 1.3
Fixed charge coverage ratio	2.9
Minimum debt covenant fixed charge coverage ratio	1.2
Amount of secured debt available to be borrowed in accordance with public debt covenants	$ 1,320.4
Line of Credit US [Member]
Line of Credit Facility [Line Items]
Unsecured revolving credit facility	575.0
Line of Credit Europe [Member]
Line of Credit Facility [Line Items]
Maximum amount of GRE transfer to GATX relating to loans and dividends	121.5
Restricted net assets	$ 374.4
Fair Value Hedging [Member]
Line of Credit Facility [Line Items]
Derivative, Number of Instruments Held | Instrument	8	8