Summary of Significant Accounting Policies Lessor Accounting (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Renewal Term		5 years		5 years
Direct Financing Lease, Revenue				$ 0.0
Operating lease revenues		$ 181.9	$ 169.7	358.6	$ 333.3
Variable operating lease revenues		18.1	18.1	32.7	31.3
Interest income on sales-type lease receivables		0.2	0.2	0.4	0.3
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Remainder of Fiscal Year		0.6		0.6
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Two		1.1		1.1
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Three		1.1		1.1
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Four		1.1		1.1
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Year Five		1.1		1.1
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, after Year Five		10.1		10.1
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received		15.1		15.1
Less: Unearned interest income		(4.7)		(4.7)
Net investment in sales-type leases (1)	[1]	10.4		10.4
Railcar Leasing and Management Services Group [Member]
Lessor, Lease, Description [Line Items]
Remaining six months of 2023	[2]	340.7		340.7
2024	[2]	588.8		588.8
2025	[2]	475.3		475.3
2026	[2]	360.1		360.1
2027	[2]	261.4		261.4
Thereafter	[2]	400.0		400.0
Total	[2]	2,426.3		2,426.3
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Sales of Leased Railcars [Domain]
Lessor, Lease, Description [Line Items]
Profit recognized at sales-type lease commencement (1)	[3]	$ 0.0	$ 0.0	$ 0.0	$ 1.3
Minimum | Railcar Leasing and Management Services Group [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract		1 year		1 year
Maximum | Railcar Leasing and Management Services Group [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract		10 years		10 years

[1] Included in other assets in our Consolidated Balance Sheets

[2] Total contractual minimum rental revenues on operating leases relates to our wholly-owned and partially-owned subsidiaries and sub-lease rental revenues associated with the Leasing Group's operating lease obligations.

[3] Included in gains on dispositions of property – lease portfolio sales on our Consolidated Statements of Operations.