Summary of Significant Accounting Policies Lessee Accounting (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term		5 years		5 years
Lessee, Operating Lease, Option to Terminate				one year
Finance Lease, Principal Payments				$ 0.0
Operating lease expense		$ 4.6	$ 4.0	13.5	$ 11.3
Short-term lease expense		0.1	$ 0.0	0.3	0.2
Cash flows from operating activities				13.5	11.3
Right-of-use assets recognized in exchange for new lease liabilities				21.0	$ 23.7
Right-of-use assets (1)	[1]	89.9		89.9		$ 82.8
Lease liabilities (2)	[2]	$ 112.1		$ 112.1		$ 106.3
Weighted average remaining lease term		10 years		10 years		10 years 9 months 18 days
Weighted average discount rate		2.80%		2.80%		3.00%
Remaining three months of 2022		$ 5.3		$ 5.3
2023		19.9		19.9
2024		14.9		14.9
2025		12.1		12.1
2026		11.4		11.4
Thereafter		66.5		66.5
Lessee, Operating Lease, Liability, to be Paid, Total		130.1		130.1
Less: Present value adjustment		$ (18.0)		$ (18.0)
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year		1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		15 years		15 years
Railcar Leasing and Management Services Group [Member]
Lessee, Lease, Description [Line Items]
Remaining three months of 2022		$ 3.2		$ 3.2
2023		12.0		12.0
2024		8.0		8.0
2025		6.0		6.0
2026		5.7		5.7
Thereafter		8.7		8.7
Lessee, Operating Lease, Liability, to be Paid, Total		43.6		43.6
Consolidated Subsidiaries, Excluding Leasing [Member]
Lessee, Lease, Description [Line Items]
Remaining three months of 2022		2.1		2.1
2023		7.9		7.9
2024		6.9		6.9
2025		6.1		6.1
2026		5.7		5.7
Thereafter		57.8		57.8
Lessee, Operating Lease, Liability, to be Paid, Total		$ 86.5		$ 86.5

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

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