Summary of Significant Accounting Policies Lessee Accounting (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term		5 years
Lessee, Operating Lease, Option to Terminate		one year
Finance Lease, Principal Payments		$ 0.0
Operating lease expense		4.3	$ 4.2
Short-term lease expense		0.0	0.1
Cash flows from operating activities		4.3	4.2
Right-of-use assets recognized in exchange for new lease liabilities		2.1	$ 11.1
Right-of-use assets (1)	[1]	91.2		$ 93.1
Lease liabilities (2)	[2]	$ 111.5		$ 114.8
Weighted average remaining lease term		9 years 10 months 24 days		9 years 10 months 24 days
Weighted average discount rate		2.90%		2.80%
Remaining nine months of 2023		$ 15.0
2024		15.1
2025		13.4
2026		12.7
2027		12.2
Thereafter		60.2
Lessee, Operating Lease, Liability, to be Paid, Total		128.6
Less: Present value adjustment		$ (17.1)
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		14 years
Railcar Leasing and Management Services Group [Member]
Lessee, Lease, Description [Line Items]
Remaining nine months of 2023		$ 8.1
2024		7.0
2025		6.1
2026		5.8
2027		5.3
Thereafter		3.7
Lessee, Operating Lease, Liability, to be Paid, Total		36.0
Consolidated Subsidiaries, Excluding Leasing [Member]
Lessee, Lease, Description [Line Items]
Remaining nine months of 2023		6.9
2024		8.1
2025		7.3
2026		6.9
2027		6.9
Thereafter		56.5
Lessee, Operating Lease, Liability, to be Paid, Total		$ 92.6

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

[2] Included in other liabilities in our Consolidated Balance Sheets.