Financial Data of Business Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Profitability
Lease income									$ 917.8	$ 873.5	$ 905.1
Marine operating revenue									212.2	185.3	128.4
Asset remarketing income									44.6	31.4	29.8
Other income									93.3	76.6	61.6
Total Revenues									1,267.9	1,166.8	1,124.9
Share of affiliates' earnings									40.6	38.1	29.0
Total Gross Income	357.1	339.7	329.6	282.1	313.8	314.4	294.8	281.9	1,308.5	1,204.9	1,153.9
Depreciation									226.5	217.0	217.7
Interest expense, net									168.9	167.1	167.5
Operating lease expense									132.0	140.2	136.6
Total Ownership Costs									527.4	524.3	521.8
Other costs and expenses									477.6	448.4	396.4
Segment profit									303.5	232.2	235.7
SG&A									155.3	134.8	127.8
Income before Income Taxes									148.2	97.4	107.9
Income Taxes									37.4	16.6	26.5
Net Income	31.6	32.9	26.4	19.9	19.5	21.1	21.5	18.7	110.8	80.8	81.4
Selected Balance Sheet Data
Investments in Affiliated Companies	513.8				486.1				513.8	486.1	452.2
Identifiable assets	5,857.5				5,442.4				5,857.5	5,442.4	5,206.4
Capital Expenditures
Portfolio investments and capital additions									614.6	585.1	480.4
Rail [Member]
Profitability
Lease income									851.3	813.3	844.5
Asset remarketing income									28.1	17.4	14.0
Other income									86.6	72.3	57.9
Total Revenues									966.0	903.0	916.4
Share of affiliates' earnings									4.4	1.2	(10.1)
Total Gross Income									970.4	904.2	906.3
Depreciation									196.1	188.8	189.1
Interest expense, net									127.1	127.1	128.7
Operating lease expense									130.9	139.1	135.5
Total Ownership Costs									454.1	455.0	453.3
Other costs and expenses									282.9	298.6	283.9
Segment profit									233.4	150.6	169.1
Selected Balance Sheet Data
Investments in Affiliated Companies	142.2				141.0				142.2	141.0	120.9
Identifiable assets	4,443.4				4,292.4				4,443.4	4,292.4	4,157.7
Capital Expenditures
Portfolio investments and capital additions									421.3	474.6	345.3
Financial Data of Business Segments (Textual) [Abstract]
Leverage level expressed as a ratio of recourse debt to equity									4
Portfolio Management [Member]
Profitability
Lease income									62.3	56.1	56.5
Asset remarketing income									16.5	14.0	15.8
Other income									4.5	1.0	2.4
Total Revenues									83.3	71.1	74.7
Share of affiliates' earnings									36.2	36.9	39.1
Total Gross Income									119.5	108.0	113.8
Depreciation									19.1	17.5	18.6
Interest expense, net									29.6	28.2	26.8
Operating lease expense									1.4	1.4	1.4
Total Ownership Costs									50.1	47.1	46.8
Other costs and expenses									21.8	12.2	15.4
Segment profit									47.6	48.7	51.6
Selected Balance Sheet Data
Investments in Affiliated Companies	371.6				345.1				371.6	345.1	331.3
Identifiable assets	844.0				741.0				844.0	741.0	672.9
Capital Expenditures
Portfolio investments and capital additions									172.0	97.4	119.5
Financial Data of Business Segments (Textual) [Abstract]
Leverage level expressed as a ratio of recourse debt to equity									3
ASC [Member]
Profitability
Lease income									4.2	4.1	4.1
Marine operating revenue									212.2	185.3	128.4
Other income									1.1	0.2	0.2
Total Revenues									217.5	189.6	132.7
Total Gross Income									217.5	189.6	132.7
Depreciation									11.3	10.7	10.0
Interest expense, net									7.7	8.3	9.0
Total Ownership Costs									19.0	19.0	19.0
Other costs and expenses									171.2	142.0	97.6
Segment profit									27.3	28.6	16.1
Selected Balance Sheet Data
Identifiable assets	276.1				271.3				276.1	271.3	269.2
Capital Expenditures
Portfolio investments and capital additions									17.4	9.0	7.2
Financial Data of Business Segments (Textual) [Abstract]
Leverage level expressed as a ratio of recourse debt to equity									1.5
Other [Member]
Profitability
Other income									1.1	3.1	1.1
Total Revenues									1.1	3.1	1.1
Total Gross Income									1.1	3.1	1.1
Interest expense, net									4.5	3.5	3.0
Operating lease expense									(0.3)	(0.3)	(0.3)
Total Ownership Costs									4.2	3.2	2.7
Other costs and expenses									1.7	(4.4)	(0.5)
Segment profit									(4.8)	4.3	(1.1)
Selected Balance Sheet Data
Identifiable assets	294.0				137.7				294.0	137.7	106.6
Capital Expenditures
Portfolio investments and capital additions									$ 3.9	$ 4.1	$ 8.4