Restructuring (Benefits) Charges (Charges and Changes to Restructuring)(Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			$ 20.0
Benefits	$ (0.2)	$ 8.0	(2.1)	$ 27.4
Cash Payments			(16.9)
Other			0.1
Restructuring liability, ending balance	1.1		1.1
Severance
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			17.7
Benefits			(1.1)
Cash Payments			(15.6)
Other			0.1
Restructuring liability, ending balance	1.1		1.1
Contract terminations and other
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning balance			2.3
Benefits			(1.0)
Cash Payments			(1.3)
Other			0.0
Restructuring liability, ending balance	$ 0.0		$ 0.0