Summary of Significant Accounting Policies Lessor Accounting (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Renewal Term		5 years		5 years
Direct Financing Lease, Revenue				$ 0.0
Operating lease revenues		$ 194.5	$ 183.4	582.3	$ 542.0
Variable operating lease revenues		14.7	18.3	49.2	51.0
Interest income on sales-type lease receivables		0.2	$ 0.1	0.5	$ 0.5
Sales-Type and Direct Financing Leases, Lease Receivable, to be Received, Remainder of Fiscal Year		0.3		0.3
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		9.0		9.0
Sales-type and Direct Financing Leases, Lease Receivable, Payments to be Received		13.7		13.7
Less: Unearned interest income		(3.8)		(3.8)
Net investment in sales-type leases (1)	[1]	9.9		9.9
Railcar Leasing and Services Group [Member]
Lessor, Lease, Description [Line Items]
Remaining three months of 2024	[2]	186.1		186.1
2025	[2]	660.8		660.8
2026	[2]	535.2		535.2
2027	[2]	406.1		406.1
2028	[2]	258.0		258.0
Thereafter	[2]	402.3		402.3
Total	[2]	$ 2,448.5		$ 2,448.5
Minimum | Railcar Leasing and Services Group [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract		1 year		1 year
Maximum | Railcar Leasing and 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.