Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Allowance for doubtful accounts	$ 114.9	$ 115.7
OTHER ASSETS:
Accumulated amortization on intangible assets	$ 373.8	$ 367.7
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)	117,043,224	116,795,899
Treasury stock at cost (in shares)	57,308,380	56,044,485