Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Designated as hedging instrument Expired hedges 2006 secured railcar equipment notes		Sep. 30, 2013 Designated as hedging instrument Expired hedges Promissory notes		Sep. 30, 2013 Designated as hedging instrument Expired hedges TRIP Holdings warehouse loan		Sep. 30, 2013 Designated as hedging instrument Open hedges Promissory notes		Sep. 30, 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		$ 421.6		$ 70.0		$ 94.1
Interest Rate			4.87%	[1]	5.34%	[1]	3.60%	[1]	4.13%	[1]	2.62%	[1]
Liability			0		0		0		25.5		2.8
AOCL – loss/ (income)	22.5	34.8	(1.7)		4.9		13.5		23.5		1.2
Noncontrolling Interest			$ 0		$ 0		$ 16.6		$ 0		$ 1.5

[1] Weighted average fixed interest rate