Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Components of accumulated other comprehensive loss
Currency translation adjustments, Beginning Balance	$ (16.5)
Currency translation adjustments, Other comprehensive loss before reclassifications	0
Currency translation adjustments, Amounts reclassified from accumulated other comprehensive loss, net of tax expense of $0.0	0
Currency translation adjustments, Amounts reclassified from accumulated other comprehensive loss, tax expense	0
Currency translation adjustments, Less: noncontrolling interest	0
Currency translation adjustments, Other comprehensive income	0
Currency translation adjustments, Ending Balance	(16.5)
Unrealized loss on derivative financial instruments, Beginning Balance	(34.8)
Unrealized loss on derivative financial instruments, Other comprehensive loss before reclassifications	(0.7)		1.6
Unrealized loss on derivative financial instruments, Amounts reclassified from accumulated other comprehensive loss, net of tax expense of $2.8	4.6		1.3
Unrealized loss on derivative financial instruments, Amounts reclassified from accumulated other comprehensive loss, tax expense	2.8		1.0
Unrealized loss on derivative financial instruments, Less: noncontrolling interest	(0.7)
Unrealized loss on derivative financial instruments, Other comprehensive income	3.2
Unrealized loss on derivative financial instruments, Purchase of additional interest in partially-owned leasing subsidiary	(2.5)
Unrealized loss on derivative financial instruments, Ending Balance	(34.1)
Net actuarial gains/(losses) of defined benefit plans, Beginning Balance	(98.8)
Net actuarial gains/(losses) of defined benefit plans, Other comprehensive loss before reclassifications	0
Net actuarial gains/(losses) of defined benefit plans, Amounts reclassified from accumulated other comprehensive loss, net of tax expense of $0.5	0.7		0.6
Net actuarial gains/(losses) of defined benefit plans, Amounts reclassified from accumulated other comprehensive loss, tax expense	0.5		0.3
Net actuarial gains/(losses) of defined benefit plans, Less: noncontrolling interest	0
Net actuarial gains/(losses) of defined benefit plans, Other comprehensive income	0.7
Net actuarial gains/(losses) of defined benefit plans, Ending Balance	(98.1)
Accumulated Other Comprehensive Loss, Beginning Balance	(150.1)
Accumulated Other Comprehensive Loss, Other comprehensive loss before reclassifications	(0.7)
Accumulated Other Comprehensive Loss, Amounts reclassified from accumulated other comprehensive loss, net of tax expense of $3.3	5.3
Accumulated Other Comprehensive Loss, Amounts reclassified from accumulated other comprehensive loss, tax expense	3.3
Accumulated Other Comprehensive Loss, Less: noncontrolling interest	(0.7)
Accumulated Other Comprehensive Loss, Other comprehensive income	3.9
Accumulated Other Comprehensive Loss, Ending Balance	(148.7)	[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	$ 1.0

[1] (unaudited)