Investment securities - Proceeds/realized gains/losses (Details 4) - CHF (SFr)
SFr in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Proceeds from sales, realized gains and realized losses from available-for-sale securities      
Proceeds from sales SFr 0 SFr 629 SFr 6
Realized gains 0 42 0
Bank      
Proceeds from sales, realized gains and realized losses from available-for-sale securities      
Proceeds from sales 0 629 SFr 6
Realized gains SFr 0 SFr 42