Railcar Leasing and Management Services Group - Selected consolidating financial information for the Leasing Group (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Cash and cash equivalents		$ 49.7		$ 49.7		$ 167.3
Receivables, net of allowance		270.2		270.2		227.6
Property, Plant and Equipment, Net		6,944.1		6,944.1		6,846.9
Restricted cash		256.8		256.8		135.1
Other assets		305.6		305.6		266.5
Total assets		8,624.8		8,624.8		8,235.9
Total debt		5,539.1		5,539.1		5,170.6
Deferred income taxes		1,115.3		1,115.3		1,106.8
Other liabilities		144.9		144.9		147.9
Total liabilities		7,368.6		7,368.6		6,939.1
Noncontrolling interest		258.6		258.6		267.0
Total Equity		997.6		997.6		1,029.8
Loss on extinguishment of debt		1.5	$ 11.7	1.5	$ 11.7
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		2.2		2.2		3.4
Receivables, net of allowance		100.7		100.7		100.8
Property, Plant and Equipment, Net		7,379.2		7,379.2		7,276.7
Restricted cash		256.8		256.8		135.1
Other assets		111.7		111.7		69.4
Total assets		7,850.6		7,850.6		7,585.4
Accounts payable and accrued liabilities		146.8		146.8		143.5
Total debt		5,020.2		5,020.2		4,771.9
Deferred income taxes		1,129.7		1,129.7		1,115.3
Other liabilities		42.2		42.2		35.6
Total liabilities		6,338.9		6,338.9		6,066.3
Noncontrolling interest		258.6		258.6		267.0
Total Equity		1,253.1		1,253.1		1,252.1
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Property, Plant and Equipment, Net		(781.6)		(781.6)		(779.1)
Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		2.2		2.2		3.4
Receivables, net of allowance		100.7		100.7		100.8
Property, Plant and Equipment, Net		6,597.6		6,597.6		6,497.6
Restricted cash		256.8		256.8		135.1
Other assets		111.7		111.7		69.4
Total assets		7,069.0		7,069.0		6,806.3
Accounts payable and accrued liabilities		146.8		146.8		143.5
Total debt		5,020.2		5,020.2		4,771.9
Deferred income taxes		945.1		945.1		938.7
Other liabilities		42.2		42.2		35.6
Total liabilities		6,154.3		6,154.3		5,889.7
Noncontrolling interest		258.6		258.6		267.0
Total Equity		656.1		656.1		649.6
Wholly-owned subsidiaries | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		2.2		2.2		3.4
Receivables, net of allowance		88.4		88.4		90.7
Property, Plant and Equipment, Net		5,844.4		5,844.4		5,706.1
Restricted cash		179.4		179.4		76.5
Other assets		109.8		109.8		67.3
Total assets		6,224.2		6,224.2		5,944.0
Accounts payable and accrued liabilities		109.8		109.8		113.4
Total debt		3,813.6		3,813.6		3,555.8
Deferred income taxes		1,128.8		1,128.8		1,114.2
Other liabilities		42.2		42.2		35.6
Total liabilities		5,094.4		5,094.4		4,819.0
Noncontrolling interest		0.0		0.0		0.0
Total Equity		1,129.8		1,129.8		1,125.0
Partially-owned subsidiaries | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		0.0		0.0		0.0
Receivables, net of allowance		12.3		12.3		10.1
Property, Plant and Equipment, Net		1,534.8		1,534.8		1,570.6
Restricted cash		77.4		77.4		58.6
Other assets		1.9		1.9		2.1
Total assets		1,626.4		1,626.4		1,641.4
Accounts payable and accrued liabilities		37.0		37.0		30.1
Total debt		1,206.6		1,206.6		1,216.1
Deferred income taxes		0.9		0.9		1.1
Other liabilities		0.0		0.0		0.0
Total liabilities		1,244.5		1,244.5		1,247.3
Noncontrolling interest		258.6		258.6		267.0
Total Equity		123.3		123.3		127.1
Consolidated Subsidiaries, Leasing [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		0.0		0.0		0.0
Receivables, net of allowance		0.0		0.0		0.0
Property, Plant and Equipment, Net	[1]	(781.6)		(781.6)		(779.1)
Restricted cash		0.0		0.0		0.0
Other assets		0.0		0.0		0.0
Total assets	[1]	(781.6)		(781.6)		(779.1)
Accounts payable and accrued liabilities		0.0		0.0		0.0
Total debt		0.0		0.0		0.0
Deferred income taxes	[1]	(184.6)		(184.6)		(176.6)
Other liabilities		0.0		0.0		0.0
Total liabilities	[1]	(184.6)		(184.6)		(176.6)
Noncontrolling interest		0.0		0.0		0.0
Total Equity	[1]	$ (597.0)		$ (597.0)		$ (602.5)

[1] Net deferred profit on railcars sold to the Leasing Group consists of intersegment profit that is eliminated in consolidation. Net deferred profit and the related deferred tax impact are included as adjustments to the property, plant, and equipment, net and deferred income taxes line items, respectively, in the Eliminations – Lease Subsidiary column above to reflect the net book value of the railcars purchased by the Leasing Group from the Rail Products Group based on manufacturing cost. See Note 5 and Note 8 for a further discussion regarding our investment in our partially-owned leasing subsidiaries and the related indebtedness.