Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Receivables allowance	$ 7.5	$ 6.6
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized shares (in shares)	5,000,000.0	5,000,000.0
Preferred stock, unissued shares (in shares)	5,000,000.0	5,000,000.0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares (in shares)	200,000,000.0	200,000,000.0
Common stock, shares outstanding (in shares)	53,200,000	55,700,000
Treasury, shares (in shares)	25,200,000	22,700,000