CECL - Financial instruments measured at amortized cost and credit losses (Details 1) - CHF (SFr)
SFr in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Overview of financial instruments measured at amortized cost, by balance sheet position [Line Items]    
Collateral Dependent Financial Assets, Collateral Coverage Ratio, Recovery Mgt Investment Bank/Asia Pacific 92.00% 89.00%
Collateral Dependent Financial Assets, Collateral Coverage Ratio, Recovery Mgt International Wealth Management 87.00% 89.00%
Collateral Dependent Financial Assets, Collateral Coverage Ratio, Recovery Mgt Swiss Universal Bank 86.00% 88.00%
Accrued interest excluded from amortized cost base of total Financial assets held-at-amortized cost, before allowance of credit losses SFr 301 SFr 351
Financial Assets, Held-to-Maturity, Cost Practical Expedient, Excluded Accrued Interest [true false] true  
Allowance for credit losses on accrued interest excluded from amortized cost base of total Financial assets held at amortized cost SFr 0 0
Accrued interest excluded from amortized cost base of total Interest-bearing deposits with banks SFr 1 1
Interest Bearing Deposits Banks, Practical Expedient, Excluded Accrued Interest [true false] true  
Accrued interest excluded from amortized cost base of total Securities purchased under resale agreements and securities borrowing transactions SFr 1  
Reverse Repos and Securities Borrowing, Practical Expedient, Excluded Accrued Interest [true false] true  
Accrued interest excluded from amortized cost base of total Loans held at amortized cost SFr 295 334
Financing Receivable, Practical Expedient, Accrued Interest Exclusion [true false] true  
Accrued interest excluded from amortized cost base of total Brokerage receivables SFr 4 16
Brokerage receivables, Practical Expedient, Excluded Accrued Interest [true false] true  
Financing Receivables,Accrued Interest on Nonaccrual Loans Included SFr 86 88
Bank    
Overview of financial instruments measured at amortized cost, by balance sheet position [Line Items]    
Accrued interest excluded from amortized cost base of total Financial assets held-at-amortized cost, before allowance of credit losses SFr 301 351
Financial Assets, Held-to-Maturity, Cost Practical Expedient, Excluded Accrued Interest [true false] true  
Allowance for credit losses on accrued interest excluded from amortized cost base of total Financial assets held at amortized cost SFr 0 0
Accrued interest excluded from amortized cost base of total Interest-bearing deposits with banks SFr 1 1
Interest Bearing Deposits Banks, Practical Expedient, Excluded Accrued Interest [true false] true  
Accrued interest excluded from amortized cost base of total Securities purchased under resale agreements and securities borrowing transactions SFr 1  
Reverse Repos and Securities Borrowing, Practical Expedient, Excluded Accrued Interest [true false] true  
Accrued interest excluded from amortized cost base of total Loans held at amortized cost SFr 295 334
Financing Receivable, Practical Expedient, Accrued Interest Exclusion [true false] true  
Accrued interest excluded from amortized cost base of total Brokerage receivables SFr 4 16
Brokerage receivables, Practical Expedient, Excluded Accrued Interest [true false] true  
Financing Receivables,Accrued Interest on Nonaccrual Loans Included SFr 85 SFr 87