Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current Assets:
Allowance for doubtful accounts	$ 115.3	$ 115.7
Other Assets:
Accumulated amortization on intangible assets	$ 380.2	$ 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)	117,177,349	116,795,899
Treasury stock at cost (in shares)	57,939,712	56,044,485