Special items Severance and Other Employee Related (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2015 employee	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
MCI [Member]
Restructuring Cost and Reserve [Line Items]
Expected reduction in number of employees | employee	125
Severance and other employee-related costs [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		$ 15.5	$ 24.7
Charges incurred		3.9	8.9
Payments made		(10.5)	(15.9)
Changes in estimates		(1.2)
Foreign currency and other adjustments		(0.7)	(0.5)
Ending balance of restructuring accruals		7.0	17.2
Severance and other employee-related costs [Member] | Canada [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		3.8	9.7
Charges incurred		0.0	7.6
Payments made		(2.8)	(10.7)
Changes in estimates		0.0
Foreign currency and other adjustments		(0.4)	(0.3)
Ending balance of restructuring accruals		0.6	6.3
Severance and other employee-related costs [Member] | Europe [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		11.5	13.6
Charges incurred		0.7	1.0
Payments made		(6.4)	(4.0)
Changes in estimates		(1.2)
Foreign currency and other adjustments		(0.3)	(0.2)
Ending balance of restructuring accruals		4.3	10.4
Severance and other employee-related costs [Member] | MCI [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		0.0	0.5
Charges incurred		3.2	0.0
Payments made		(1.1)	(0.4)
Changes in estimates		0.0
Foreign currency and other adjustments		0.0	0.0
Ending balance of restructuring accruals		2.1	0.1
Severance and other employee-related costs [Member] | Corporate [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		0.2	0.9
Charges incurred		0.0	0.3
Payments made		(0.2)	(0.8)
Changes in estimates		0.0
Foreign currency and other adjustments		0.0	0.0
Ending balance of restructuring accruals		$ 0.0	$ 0.4
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Payment of severance obligations, term		12 months
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Payment of severance obligations, term		15 months