Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Allowance for doubtful accounts	$ 113.6	$ 98.2
OTHER ASSETS:
Accumulated amortization on intangible assets	$ 333.3	$ 299.8
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)	116,274,608	115,115,748
Treasury stock at cost (in shares)	50,022,411	48,146,658