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Special Charges (Narrative)(Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Actuarial (gain) loss from remeasurement, net									$ 25.8	$ (1.4)
Termination benefit costs									3.5	0.4
Other restructuring costs									6.3	1.0
Payments for Restructuring									(2.5)	(3.6)
Restructuring Reserve	$ 6.5				$ 5.5				6.5	5.5	$ 8.7
Restructuring Reserve, Current	3.1								3.1
Restructuring Reserve, Noncurrent	2.6								2.6
Restructuring Charges	2.4	$ 2.4	$ 2.3	$ 2.4	0.2	$ 0.6	$ 0.6	$ 0.0	9.5	1.4
Contract Termination [Member]
Termination benefit costs									1.1	0.1
Payments for Restructuring									(0.8)	(3.1)
Restructuring Reserve	5.7				5.4				5.7	5.4	8.4
Other Restructuring [Member]
Termination benefit costs									2.4	0.3
Payments for Restructuring									(1.7)	(0.5)
Restructuring Reserve	$ 0.8				$ 0.1				$ 0.8	$ 0.1	$ 0.3