CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowance for credit losses	$ 1.1	$ 1.0
Accumulated depreciation	$ 385.7	$ 381.6
Capital Stock, par value (in dollars per share)	$ 1	$ 1
Capital Stock, authorized shares (in shares)	50.0	50.0
Capital Stock, shares issued (in shares)	18.6	18.6
Capital Stock, shares outstanding (in shares)	18.6	18.6