New Accounting Standards (Summary of Adoption of ASU 2017-07) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses									$ 2,972.1	$ 3,231.0	$ 3,136.9
Operating profit	$ (49.6)	$ 186.9	$ 53.0	$ 44.9	$ 131.5	$ 87.3	$ 32.7	$ 29.8	235.2	281.3	323.8
Other expense, net									(7.1)	(34.6)	(172.9)
Income before income taxes	$ (84.1)	$ 182.1	$ (0.3)	$ 10.4	$ 91.6	$ 48.0	$ (12.2)	$ (6.7)	$ 108.1	120.7	31.2
As originally reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses										3,239.0	3,138.8
Operating profit										273.3	321.9
Other expense, net										(26.6)	(171.0)
Income before income taxes										120.7	31.2
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating profit										8.0	1.9
Accounting Standards Update 2017-07 | Impact of adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling, general and administrative expenses										(8.0)	(1.9)
Operating profit										8.0	1.9
Other expense, net										(8.0)	(1.9)
Income before income taxes										$ 0.0	$ 0.0