Summary of Significant Accounting Policies Lessor Accounting (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Renewal Term		5 years		5 years
Lessor, Operating Lease, Termination Option Term				one year
Sales-type lease revenues		$ 0.0		$ 0.0
Direct Financing Lease, Revenue		0.0		0.0
Operating lease revenues		165.0	$ 165.1	328.0	$ 337.3
Variable operating lease revenues		12.5	$ 10.6	25.9	$ 23.2
Railcar Leasing and Management Services Group [Member]
Lessor, Lease, Description [Line Items]
Remaining six months of 2021	[1]	288.0		288.0
2022	[1]	478.9		478.9
2023	[1]	358.9		358.9
2024	[1]	268.2		268.2
2025	[1]	187.1		187.1
Thereafter	[1]	347.1		347.1
Total	[1]	$ 1,928.2		$ 1,928.2
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] 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.