Name:	cs_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentImpairmentLossCumulativeAmount
Namespace Prefix:	cs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. This element represents information relating to other investments.

No definition available.

Name:	cs_InvestmentOtherLineItems
Namespace Prefix:	cs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

This item represents the revenues from other investments which are not included in another category or item, including realized gains and losses from the sale of other investments, impairment losses and unrealized gains or losses on other investment accounted for under the fair value option.

No definition available.

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

Amount of impairment loss on investment in equity security without readily determinable fair value.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479536/321-10-50-3

Name:	us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of cumulative impairment loss on investment in equity security without readily determinable fair value.