CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Accounts receivable, allowances	$ 27.0	$ 25.7
Property and equipment, accumulated depreciation	$ 645.7	$ 595.5
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Treasury stock, shares	151,865,749	152,208,231
Series common stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	10,000,000	10,000,000
Common Stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	342,902,272	342,902,272