Railcar Leasing and Management Services Group (Details Textual) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended			19 Months Ended
	Feb. 28, 2015	Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Dec. 31, 2014
Railcar Leasing and Management Services Group (Textual) [Abstract]
Revenue		$ 1,676.8		$ 1,485.3	$ 3,303.5		$ 2,945.8
Proceeds from railcar lease fleet sales owned more than one year at the time of sale					167.4		242.1
Assets purchased from the Trust					419.4		49.5
Assets		8,632.2	[1]		8,632.2	[1]		$ 8,632.2	[1]	$ 8,733.8
Rail Group
Railcar Leasing and Management Services Group (Textual) [Abstract]
Revenue		884.2		760.7	1,759.6		1,361.8
Railcar Leasing and Management Services Group
Railcar Leasing and Management Services Group (Textual) [Abstract]
Revenue		231.4		225.4	475.6		667.6
Operating lease obligations guaranteed by Trinity Industries, Inc. and certain subsidiaries		15.5			15.5			15.5
Railcar Leasing and Management Services Group | Wholly-owned subsidiaries
Railcar Leasing and Management Services Group (Textual) [Abstract]
Net book value of equipment pledged as collateral for leasing group debt		1,525.4			1,525.4			1,525.4
Net book value of equipment securing capital lease obligations		44.8			44.8			44.8
Net book value of unpledged equipment		1,326.2			1,326.2			1,326.2
Railcar Leasing and Management Services Group | TRIP Holdings
Railcar Leasing and Management Services Group (Textual) [Abstract]
Net book value of equipment pledged as collateral for leasing group debt		1,375.0			1,375.0			1,375.0
Railcar Leasing and Management Services Group | TRL 2012
Railcar Leasing and Management Services Group (Textual) [Abstract]
Net book value of equipment pledged as collateral for leasing group debt		591.0			$ 591.0			591.0
Railcar Leasing and Management Services Group | Wholly-owned qualified subsidiaries for leasing railcars from the Trusts
Railcar Leasing and Management Services Group (Textual) [Abstract]
Period of railcars leased from the Trusts under operating leases (in years)					22 years
Assets purchased from the Trust	$ 121.1
Remaining future operating lease obligations terminated	$ 105.8
Assets		146.8			$ 146.8			146.8
Cash		52.4			52.4			52.4
Railcars		67.4			$ 67.4			67.4
Railcar Leasing and Management Services Group | Minimum
Railcar Leasing and Management Services Group (Textual) [Abstract]
Term of leases with third parties (in years)					1 year
Railcar Leasing and Management Services Group | Maximum
Railcar Leasing and Management Services Group (Textual) [Abstract]
Term of leases with third parties (in years)					20 years
Railcars owned one year or less at the time of sale | Railcar Leasing and Management Services Group
Railcar Leasing and Management Services Group (Textual) [Abstract]
Revenue		$ 59.9		$ 70.8	$ 138.6		363.7
Element
Railcar Leasing and Management Services Group (Textual) [Abstract]
Proceeds from the sale of leased railcars					349.2		635.7	$ 1,336.9
Element | Rail Group
Railcar Leasing and Management Services Group (Textual) [Abstract]
Proceeds from the sale of leased railcars					111.7		81.6
Element | Railcars owned one year or less at the time of sale | Railcar Leasing and Management Services Group
Railcar Leasing and Management Services Group (Textual) [Abstract]
Proceeds from the sale of leased railcars					$ 110.0		$ 331.4

[1] (unaudited)