Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 115.9	$ 121.6
Other Assets:
Accumulated amortization on intangible assets	$ 448.7	$ 441.3
SHAREHOLDERS' EQUITY:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	25,000,000	25,000,000
Preferred stock, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	125,000,000	125,000,000
Common stock, issued (in shares)	118,009,931	117,762,065
Treasury stock at cost (in shares)	65,943,910	64,165,136