Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Changes in accumulated other comprehensive loss
Beginning balance				$ 4,048.7
Other comprehensive income (loss), net of tax, before reclassifications				1.1
Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $-, $0.5, $1.0, and $1.5				3.8
Amounts reclassified from accumulated other comprehensive loss, tax benefit				1.5
Less: noncontrolling interest		$ (2.0)	$ (4.6)	(4.9)	$ (5.1)
Other comprehensive income				3.7
Ending balance	[1]	4,177.3		4,177.3
Currency translation adjustments
Changes in accumulated other comprehensive loss
Beginning balance				(24.5)
Other comprehensive income (loss), net of tax, before reclassifications				1.8
Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $-, $0.5, $1.0, and $1.5				0.0
Amounts reclassified from accumulated other comprehensive loss, tax benefit				0.0
Other comprehensive income				1.8
Ending balance		(22.7)		(22.7)
Currency translation adjustments, noncontrolling interest
Changes in accumulated other comprehensive loss
Less: noncontrolling interest				0.0
Unrealized loss on derivative financial instruments
Changes in accumulated other comprehensive loss
Beginning balance				(1.3)
Other comprehensive income (loss), net of tax, before reclassifications				(0.7)
Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $-, $0.5, $1.0, and $1.5				2.2
Amounts reclassified from accumulated other comprehensive loss, tax benefit				0.5
Other comprehensive income				0.3
Ending balance		(1.0)		(1.0)
Unrealized loss on derivative financial instruments, noncontrolling interest
Changes in accumulated other comprehensive loss
Less: noncontrolling interest				(1.2)
Net actuarial gains/(losses) of defined benefit plans
Changes in accumulated other comprehensive loss
Beginning balance				(89.6)
Other comprehensive income (loss), net of tax, before reclassifications				0.0
Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $-, $0.5, $1.0, and $1.5				1.6
Amounts reclassified from accumulated other comprehensive loss, tax benefit				1.0
Other comprehensive income				1.6
Ending balance		(88.0)		(88.0)
Net actuarial gains/(losses) of defined benefit plans, noncontrolling interest
Changes in accumulated other comprehensive loss
Less: noncontrolling interest				0.0
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive loss
Beginning balance				(115.4)
Less: noncontrolling interest				(3.7)
Ending balance		(111.7)		(111.7)
Accumulated Other Comprehensive Loss, noncontrolling interest
Changes in accumulated other comprehensive loss
Beginning balance				394.8
Less: noncontrolling interest				(1.2)
Ending balance		$ 394.2		394.2
Cost of revenues
Changes in accumulated other comprehensive loss
Before-tax reclassification of net actuarial gains/(losses) of defined benefit plans included in cost of revenues				$ 2.0

[1] (unaudited)