Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Designated as hedging instrument Expired hedges 2006 secured railcar equipment notes		Mar. 31, 2013 Designated as hedging instrument Expired hedges Promissory notes		Mar. 31, 2013 Designated as hedging instrument Expired hedges TRIP Holdings warehouse loan		Mar. 31, 2013 Designated as hedging instrument Open hedges Promissory notes		Mar. 31, 2013 Designated as hedging instrument Open hedges TRIP Master Funding secured railcar equipment notes		Jul. 31, 2011 Designated as hedging instrument Open hedges TRIP Master Funding secured railcar equipment notes
Interest rate hedges included in balance sheet
Notional Amount			$ 200.0		$ 370.0		$ 788.5		$ 435.7		$ 75.6		$ 94.1
Interest Rate			4.87%	[1]	5.34%	[1]	3.60%	[1]	4.13%	[1]	2.62%	[1]
Liability			0		0		0		33.3		4.4
AOCL - loss/(income)	34.1	34.8	(1.9)		6.4		24.1		31.1		3.2
Noncontrolling Interest			$ 0		$ 0		$ 8.7		$ 0		$ 1.2

[1] Weighted average fixed interest rate