Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Interest Rate Locks, 2005 to 2006 [Member]	Mar. 31, 2012 Interest Rate Locks, 2006 to 2007 [Member]	Mar. 31, 2012 Interest Rate Locks, TRIP Holdings [Member]	Mar. 31, 2012 Interest Rate Swap TRIP Rail Master Funding Secured Railcar Equipment Notes [Member]	Jul. 31, 2011 Interest Rate Swap TRIP Rail Master Funding Secured Railcar Equipment Notes [Member]	Mar. 31, 2012 Interest Rate Swap, 2008 Debt Issuance [Member]
Interest rate hedges included in balance sheet
Notional Amount			$ 200.0	$ 370.0	$ 788.5	$ 86.7	$ 94.1	$ 467.2
Interest Rate			4.87%	5.34%	3.60%	2.62%		4.13%
Liability						4.2		46.2
AOCL loss/(income)	43.8	46.2	(2.2)	9.7	22.5	2.4		44.4
Noncontrolling Interest					$ 16.9	$ 1.8