Railcar Leasing and Management Services Group (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		16 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	$ 1,626.7	$ 1,460.5
Proceeds from railcar lease fleet sales owned more than one year at the time of sale	78.5	224.3
Railcar Leasing and Management Services Group
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	244.2	442.2
Rail Group
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	875.4	601.1
Element
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Proceeds from the sale of leased railcars	127.0	514.3	1,114.7
Element | Rail Group
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	15.2	13.7
Railcars owned one year or less at the time of sale | Railcar Leasing and Management Services Group
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	78.7	292.9
Railcars owned one year or less at the time of sale | Element | Railcar Leasing and Management Services Group
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	50.1	277.9
Proceeds from railcar lease fleet sales owned more than one year at the time of sale	$ 61.7	$ 222.7