Derivatives and Hedging (Details)	3 Months Ended
	Mar. 31, 2012
Cash flow hedges
Foreign Exchange Risk Management
Foreign currency exposures, maximum average hedging period (in years)	2 years
Foreign currency exposures, maximum hedging period (in years)	P5Y
Interest Rate Risk Management
Interest rate fluctuations, maximum hedging period (in years)	2 years
Net investment hedges
Foreign Exchange Risk Management
Foreign currency exposures, maximum hedging period (in years)	2 years
Not designated as hedging instrument
Foreign Exchange Risk Management
Foreign currency exposures, maximum hedging period (in years)	1 year