Provision for credit losses (Details) - CHF (SFr)
SFr in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2021
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Provision for credit losses              
Loans held at amortized cost         SFr (23) SFr 863 SFr 284
Other financial assets held at amortized cost         4,291 24 11
Off-balance sheet credit exposures         (63) 209 29
Provision for credit losses         4,205 1,096 324
Archegos Capital Management [Member]              
Provision for credit losses              
Other financial assets held at amortized cost SFr (5) SFr (188) SFr 70 SFr 4,430 4,307    
Bank              
Provision for credit losses              
Loans held at amortized cost         (23) 863 284
Other financial assets held at amortized cost         4,295 19 11
Off-balance sheet credit exposures         (63) 210 29
Provision for credit losses         4,209 SFr 1,092 SFr 324
Bank | Archegos Capital Management [Member]              
Provision for credit losses              
Other financial assets held at amortized cost         SFr 4,307