Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Consolidated Balance Sheets (Parenthetical) [Abstract]
Allowance for doubtful accounts	$ 26.8	$ 32.1
Accumulated depreciation	1,185.0	1,279.2
Intangible assets, accumulated amortization	$ 737.4	$ 879.9
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	7.5	7.5
Preferred stock, shares issued	0.0	0.0
Common stock, par value	$ 0.15	$ 0.15
Common stock, shares authorized	1,000.0	1,000.0
Common stock, shares issued	297.2	297.2
Common stock, shares outstanding	223.9	230.1
Treasury stock, shares	73.3	67.1