Financial Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Derivatives
Derivative Instruments Not Designated as Hedging Instruments, Gain	$ 1.0
Derivative instruments maturity period (in months)	36 months
Derivative, Notional Amount	565.7		619.8
Deferred tax expense (benefit)	3.1		(1.0)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	4.7		(1.5)
Deferred gain on derivative instruments reclassified from OCI to earnings during the next the next twelve months, before tax	8.9
Deferred gain on derivative instruments reclassified from OCI to earnings during next twelve months, net of tax	5.5
Derivative Instruments Not Designated as Hedging Instruments, Loss		(0.5)
Aggregate fair value of derivative instruments in liability positions	16.5
Collateral Already Posted, Aggregate Fair Value	0
Trading Securities, Fair Value Disclosure	19.2
interest-bearing deposits, fair value	19.0
Forward Contracts PHP [Member]
Derivatives
Notional Amount of Foreign Currency Derivative Purchase Contracts	16,551.5
Notional value of foreign currency cash flow derivatives	365.6
Forward Contracts INR [Member]
Derivatives
Notional Amount of Foreign Currency Derivative Purchase Contracts	8,219.1
Notional value of foreign currency cash flow derivatives	157.2
Forward Contracts CAD [Member]
Derivatives
Notional Amount of Foreign Currency Derivative Purchase Contracts	6.0
Notional value of foreign currency cash flow derivatives	5.7
Forward Contracts COP [Member]
Derivatives
Notional Amount of Foreign Currency Derivative Purchase Contracts	23,400.0
Notional value of foreign currency cash flow derivatives	11.9
Forward Contracts AUD [Member]
Derivatives
Notional Amount of Foreign Currency Derivative Sale Contracts	24.6
Notional value of foreign currency cash flow derivatives	$ 25.3