Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Receivables allowance	$ 7.9	$ 6.6
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized shares	5,000,000.0	5,000,000.0
Preferred stock, unissued shares	5,000,000.0	5,000,000.0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares	200,000,000.0	200,000,000.0
Common stock, shares outstanding	54,900,000	55,700,000
Treasury, shares	23,500,000	22,700,000