Business developments (Details 3) In Millions, unless otherwise specified	Feb. 02, 2010 Crescent Holding GmbH	Apr. 21, 2011 Qatar Holding LLC
Related party disclosures
Shares held by related party	78.4	73.2
Portion of registered Group shares held by related party (as a percent)	6.60%	6.20%

This element represents the percentage of registered shares in the reporting entity held by the related party.

No definition available.

Name:	cs_EquityInvestmentsByAffiliatesPercentage
Namespace Prefix:	cs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant