CECL (Details 6)
SFr in Millions
 12 Months Ended
Dec. 31, 2021
CHF (SFr)
day
month
Dec. 31, 2020
CHF (SFr)
Dec. 31, 2019
CHF (SFr)
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets SFr 1,964 SFr 2,041 SFr 1,510
Interest income recognized 30 53  
Amortized cost of non-accrual assets with no specific allowance SFr 210 100  
Number of days of default on interest or principal considered to assess credit worthiness (in months) | month 3    
Period of anticipated repayment after which loan is written down to net book value (in days) | day 10    
Minimum [Member]      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Write-Down of Loan to Net Book Value Loan Provision Threshold as Percentage of Loan Notional Amount 90.00%    
Corporate and institutional      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets SFr 925 1,317 883
Interest income recognized 17 46  
Amortized cost of non-accrual assets with no specific allowance 96 39  
Corporate and institutional | Real estate      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 167 324 155
Interest income recognized 6 8  
Amortized cost of non-accrual assets with no specific allowance 0 27  
Corporate and institutional | Commercial and industrial loans      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 698 925 682
Interest income recognized 11 38  
Amortized cost of non-accrual assets with no specific allowance 96 4  
Corporate and institutional | Financial institutions      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 41 68 46
Interest income recognized 0 0  
Amortized cost of non-accrual assets with no specific allowance 0 8  
Corporate and institutional | Governments and public institutions      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 19 0 0
Interest income recognized 0 0  
Amortized cost of non-accrual assets with no specific allowance 0 0  
Consumer      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 1,039 724 627
Interest income recognized 13 7  
Amortized cost of non-accrual assets with no specific allowance 114 61  
Consumer | Mortgages      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 572 418 337
Interest income recognized 2 3  
Amortized cost of non-accrual assets with no specific allowance 111 60  
Consumer | Loans collateralized by securities      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 262 105 122
Interest income recognized 8 1  
Amortized cost of non-accrual assets with no specific allowance 2 0  
Consumer | Consumer finance      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 205 201 168
Interest income recognized 3 3  
Amortized cost of non-accrual assets with no specific allowance 1 1  
Bank      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 1,952 2,029 1,498
Interest income recognized 30 53  
Amortized cost of non-accrual assets with no specific allowance 210 100  
Bank | Corporate and institutional      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 913 1,305 871
Interest income recognized 17 46  
Amortized cost of non-accrual assets with no specific allowance 96 39  
Bank | Corporate and institutional | Real estate      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 167 324 155
Interest income recognized 6 8  
Amortized cost of non-accrual assets with no specific allowance 0 27  
Bank | Corporate and institutional | Commercial and industrial loans      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 686 913 670
Interest income recognized 11 38  
Amortized cost of non-accrual assets with no specific allowance 96 4  
Bank | Corporate and institutional | Financial institutions      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 41 68 46
Interest income recognized 0 0  
Amortized cost of non-accrual assets with no specific allowance 0 8  
Bank | Corporate and institutional | Governments and public institutions      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 19 0 0
Interest income recognized 0 0  
Amortized cost of non-accrual assets with no specific allowance 0 0  
Bank | Consumer      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 1,039 724 627
Interest income recognized 13 7  
Amortized cost of non-accrual assets with no specific allowance 114 61  
Bank | Consumer | Mortgages      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 572 418 337
Interest income recognized 2 3  
Amortized cost of non-accrual assets with no specific allowance 111 60  
Bank | Consumer | Loans collateralized by securities      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 262 105 122
Interest income recognized 8 1  
Amortized cost of non-accrual assets with no specific allowance 2 0  
Bank | Consumer | Consumer finance      
Loans Held At Amortized Cost, Nonaccrual [Line Items]      
Amortized cost of non-accrual assets 205 201 SFr 168
Interest income recognized 3 3  
Amortized cost of non-accrual assets with no specific allowance SFr 1 SFr 1