Derivative Financial Instruments (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair Value of Derivative Instruments in the Consolidated Balance Sheets
Assets	$ 100.9	$ 100.9
Liabilities	(163.4)	(172.1)
Assets subject to master netting agreement	100.9	100.9
Liabilities subject to master netting agreement	118.6	126.0
Net liabilities subject to master netting agreement	(17.7)	(25.1)
Derivatives designated as hedging instruments | Foreign exchange contracts
Fair Value of Derivative Instruments in the Consolidated Balance Sheets
Assets	10.8
Liabilities	(33.3)	(32.8)
Derivatives not designated as hedging instruments
Fair Value of Derivative Instruments in the Consolidated Balance Sheets
Assets	90.1	100.9
Liabilities	(130.1)	(139.3)
Derivatives not designated as hedging instruments | Interest rate contracts
Fair Value of Derivative Instruments in the Consolidated Balance Sheets
Assets	90.1	90.8
Liabilities	(129.6)	(137.7)
Derivatives not designated as hedging instruments | Foreign exchange contracts
Fair Value of Derivative Instruments in the Consolidated Balance Sheets
Assets		10.1
Liabilities	$ (0.5)	$ (1.6)