Financial instruments (Details) (CHF) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Financial instruments
Interest rate yield curves used as a reference rate	OIS
Variable rate used as a reference rate	LIBOR
Loss from change in reference rate	146

The amount of loss in determining the fair value of certain collateralized derivatives due to change in reference rate.

No definition available.

Name:	cs_FairValueMeasurementsGainLossFromChangeInReferenceRate
Namespace Prefix:	cs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration