Financial Data of Business Segments (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Profitability
Revenues	$ 314.6	$ 288.2	$ 579.6	$ 551.8
Share of affiliates' earnings	15.0	6.6	32.1	24.9
Total gross income	329.6	294.8	611.7	576.7
Ownership costs	133.7	131.1	263.5	260.0
Other costs and expenses	122.8	105.7	212.9	198.9
Segment profit (loss)	73.1	58.0	135.3	117.8
SG&A	37.4	32.8	73.8	66.3
Income before income taxes	35.7	25.2	61.5	51.5
Capital Expenditures
Portfolio investments and capital additions	163.9	60.9	260.1	131.1
Investments in Affiliated Companies	567.6		567.6		486.1
Identifiable assets	5,642.5		5,642.5		5,442.4
Rail [Member]
Profitability
Revenues	237.7	217.8	474.5	454.5
Share of affiliates' earnings	8.3	(4.7)	15.4	3.9
Total gross income	246.0	213.1	489.9	458.4
Ownership costs	114.5	113.8	229.5	227.5
Other costs and expenses	74.8	69.9	152.1	152.2
Segment profit (loss)	56.7	29.4	108.3	78.7
Capital Expenditures
Portfolio investments and capital additions	102.4	40.4	156.3	88.5
Investments in Affiliated Companies	164.4		164.4		141.0
Identifiable assets	4,458.2		4,458.2		4,292.4
Specialty [Member]
Profitability
Revenues	17.6	16.3	33.5	33.7
Share of affiliates' earnings	6.7	11.3	16.7	21.0
Total gross income	24.3	27.6	50.2	54.7
Ownership costs	12.2	11.6	24.0	22.8
Other costs and expenses	3.3	1.5	6.7	5.3
Segment profit (loss)	8.8	14.5	19.5	26.6
Capital Expenditures
Portfolio investments and capital additions	52.9	13.5	89.3	33.1
Investments in Affiliated Companies	403.2		403.2		345.1
Identifiable assets	799.5		799.5		741.0
ASC [Member]
Profitability
Revenues	58.8	53.4	70.9	62.7
Total gross income	58.8	53.4	70.9	62.7
Ownership costs	5.9	5.5	7.9	7.6
Other costs and expenses	44.3	38.8	53.6	45.6
Segment profit (loss)	8.6	9.1	9.4	9.5
Capital Expenditures
Portfolio investments and capital additions	7.4	5.4	12.6	7.0
Identifiable assets	286.3		286.3		271.3
Other [Member]
Profitability
Revenues	0.5	0.7	0.7	0.9
Total gross income	0.5	0.7	0.7	0.9
Ownership costs	1.1	0.2	2.1	2.1
Other costs and expenses	0.4	(4.5)	0.5	(4.2)
Segment profit (loss)	(1.0)	5.0	(1.9)	3.0
Capital Expenditures
Portfolio investments and capital additions	1.2	1.6	1.9	2.5
Identifiable assets	$ 98.5		$ 98.5		$ 137.7