Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Allowances for doubtful accounts	$ 50.1	$ 57.8
Preferred stock, par value (in usd per shares)	$ 0.01	$ 0.01
Preferred stock, shares authorized	500,000.0	500,000.0
Preferred stock, shares issued	0	0
Treasury stock, shares	5,900,000	6,600,000
Common Class A [Member]
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	40,000,000	40,000,000
Treasury stock, shares	4,600,000	5,300,000
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	15,000,000	15,000,000
Treasury stock, shares	800,000	800,000
Common Class C [Member]
Common stock, par value (in dollars per share)	$ 0.025	$ 0.025
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	500,000	500,000
Treasury stock, shares	500,000	500,000