Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Current Assets:
Allowances, accounts and notes receivable	$ 16.1	$ 14.4
Accumulated depreciation	$ 936.5	$ 910.8
Stockholders' equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	87,170,197	87,170,197
Treasury stock, shares	51,538,343	51,588,103