Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Components of accumulated other comprehensive loss
Currency translation adjustments, Beginning Balance				$ (16.5)
Currency translation adjustments, Other comprehensive income before reclassifications				0
Currency translation adjustments, Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $0.0				0
Currency translation adjustments, Amounts reclassified from accumulated other comprehensive loss, tax benefit				0
Currency translation adjustments, Less: noncontrolling interest				0
Currency translation adjustments, Other comprehensive income				0
Currency translation adjustments, Ending Balance	(16.5)			(16.5)
Unrealized loss on derivative financial instruments, Beginning Balance				(34.8)
Unrealized loss on derivative financial instruments, Other comprehensive income before reclassifications	(0.4)		1.5	0.4		3.4
Unrealized loss on derivative financial instruments, Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $6.8	4.4		1.3	13.7		3.9
Unrealized loss on derivative financial instruments, Amounts reclassified from accumulated other comprehensive loss, tax benefit	2.0		1.0	6.8		2.9
Unrealized loss on derivative financial instruments, Less: noncontrolling interest				(3.2)
Unrealized loss on derivative financial instruments, Other comprehensive income				10.9
Unrealized loss on derivative financial instruments, Sale of interests in partially-owned leasing subsidiaries				13.2
Unrealized loss on derivative financial instruments, Repurchase of interests in partially-owned leasing subsidiary				(11.8)
Unrealized loss on derivative financial instruments, Ending Balance	(22.5)			(22.5)
Net actuarial gains/(losses) of defined benefit plans, Beginning Balance				(98.8)
Net actuarial gains/(losses) of defined benefit plans, Other comprehensive income before reclassifications				0
Net actuarial gains/(losses) of defined benefit plans, Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $1.4	0.8		0.5	2.3		1.6
Net actuarial gains/(losses) of defined benefit plans, Amounts reclassified from accumulated other comprehensive loss, tax benefit	0.4		0.2	1.4		0.9
Net actuarial gains/(losses) of defined benefit plans, Less: noncontrolling interest				0
Net actuarial gains/(losses) of defined benefit plans, Other comprehensive income				2.3
Net actuarial gains/(losses) of defined benefit plans, Ending Balance	(96.5)			(96.5)
Accumulated Other Comprehensive Loss, Beginning Balance				(150.1)
Accumulated Other Comprehensive Loss, Other comprehensive income before reclassifications				0.4
Accumulated Other Comprehensive Loss, Amounts reclassified from accumulated other comprehensive loss, net of tax benefit of $8.2				16.0
Accumulated Other Comprehensive Loss, Amounts reclassified from accumulated other comprehensive loss, tax benefit				8.2
Accumulated Other Comprehensive Loss, Less: noncontrolling interest				(3.2)
Accumulated Other Comprehensive Loss, Other comprehensive income				13.2
Accumulated Other Comprehensive Loss, Ending Balance	(135.5)	[1]		(135.5)	[1]
Cost of revenues
Accumualted Other Comprehensive Income [Line Items]
Before-tax reclassification of net actuarial gains/(losses) of defined benefit plans included in cost of revenues				$ 3.0

[1] (unaudited)