Note 1. Summary of Significant Accounting Policies Lessee Accounting (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
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		19.5	$ 18.2	$ 15.2
Short-term lease expense		0.0	0.4	0.2
Operating Lease, Payments		19.5	18.2	15.2
Right-of-use assets recognized in exchange for new lease liabilities		$ 24.1	$ 28.8	$ 23.0
Right-of-use assets (1)	[1]	Other assets	Other assets
Lease liabilities (2)	[2]	Other liabilities	Other liabilities
Weighted average remaining lease term		9 years 3 months 18 days	9 years 10 months 24 days
Weighted average discount rate		3.60%	2.80%
2024		$ 20.1
2025		17.8
2026		16.3
2027		15.1
2028		11.6
Thereafter		58.1
Lessee, Operating Lease, Liability, to be Paid		139.0
Less: Present value adjustment		$ (20.8)
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		13 years
Railcar Leasing and Management Services Group [Member]
Lessee, Lease, Description [Line Items]
2024		$ 10.1
2025		8.8
2026		8.0
2027		7.0
2028		4.3
Thereafter		6.7
Lessee, Operating Lease, Liability, to be Paid		44.9
Consolidated Subsidiaries, Excluding Leasing [Member]
Lessee, Lease, Description [Line Items]
2024		10.0
2025		9.0
2026		8.3
2027		8.1
2028		7.3
Thereafter		51.4
Lessee, Operating Lease, Liability, to be Paid		$ 94.1

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

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