Pension and other post-retirement benefits - Plan assets measured at fair value roll-forward (Details 4) - CHF (SFr)
SFr in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period SFr 0  
End of the measurement period 5 SFr 0
Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 77  
End of the measurement period 3 77
Defined benefit pension plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 22,212  
End of the measurement period 23,098 22,212
Defined benefit pension plans | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444 1,351
Transfers In 0 0
Transfers Out 0 0
On assets still held at reporting date 65 69
On assets sold during the period 0 0
Purchases, sales, settlements 5 24
Foreign currency translation impact 0 0
End of the measurement period 1,514 1,444
Defined benefit pension plans | Level 3 | Real estate    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444 1,351
Transfers In 0 0
Transfers Out 0 0
On assets still held at reporting date 65 69
On assets sold during the period 0 0
Purchases, sales, settlements 5 24
Foreign currency translation impact 0 0
End of the measurement period 1,514 1,444
Defined benefit pension plans | Level 3 | Real estate - direct    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444 1,351
Transfers In 0 0
Transfers Out 0 0
On assets still held at reporting date 65 69
On assets sold during the period 0 0
Purchases, sales, settlements 5 24
Foreign currency translation impact 0 0
End of the measurement period 1,514 1,444
Switzerland | Defined benefit pension plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 18,000 17,790
Foreign currency translation impact 0 0
End of the measurement period 19,296 18,000
Switzerland | Defined benefit pension plans | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 5,884  
End of the measurement period 6,784 5,884
Switzerland | Defined benefit pension plans | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 5,884  
End of the measurement period 6,784 5,884
Switzerland | Defined benefit pension plans | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 5,320  
End of the measurement period 5,264 5,320
Switzerland | Defined benefit pension plans | Real estate    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 3,239  
End of the measurement period 3,554 3,239
Switzerland | Defined benefit pension plans | Real estate - direct    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444  
End of the measurement period 1,514 1,444
Switzerland | Defined benefit pension plans | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,795  
End of the measurement period 2,040 1,795
Switzerland | Defined benefit pension plans | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 3,099  
End of the measurement period 3,381 3,099
Switzerland | Defined benefit pension plans | Private equity - alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,794  
End of the measurement period 2,431 1,794
Switzerland | Defined benefit pension plans | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 414  
End of the measurement period 221 414
Switzerland | Defined benefit pension plans | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 891  
End of the measurement period 729 891
Switzerland | Defined benefit pension plans | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444 1,351
Transfers In 0 0
Transfers Out 0 0
On assets still held at reporting date 65 69
On assets sold during the period 0 0
Purchases, sales, settlements 5 24
Exchange rate gains/(losses) on investments 0 0
End of the measurement period 1,514 1,444
Switzerland | Defined benefit pension plans | Level 3 | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Real estate    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444  
End of the measurement period 1,514 1,444
Switzerland | Defined benefit pension plans | Level 3 | Real estate - direct    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,444  
End of the measurement period 1,514 1,444
Switzerland | Defined benefit pension plans | Level 3 | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Private equity - alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Switzerland | Defined benefit pension plans | Level 3 | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 4,212 4,111
Foreign currency translation impact 132 (257)
End of the measurement period 3,802 4,212
International | Defined benefit pension plans | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 3,813  
End of the measurement period 3,531 3,813
International | Defined benefit pension plans | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,637  
End of the measurement period 1,199 1,637
International | Defined benefit pension plans | Government debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 2,176  
End of the measurement period 2,332 2,176
International | Defined benefit pension plans | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 85  
End of the measurement period 101 85
International | Defined benefit pension plans | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 20  
End of the measurement period 0 20
International | Defined benefit pension plans | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period (47)  
End of the measurement period (27) (47)
International | Defined benefit pension plans | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period (47)  
End of the measurement period (27) (47)
International | Defined benefit pension plans | Other investments, plan assets    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 77  
End of the measurement period 87 77
International | Defined benefit pension plans | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Government debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Defined benefit pension plans | Level 3 | Other investments, plan assets    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
International | Other post-retirement defined benefit plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0 0
Foreign currency translation impact 0 0
End of the measurement period 0 0
Bank | International | Defined benefit pension plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 4,212 4,111
Foreign currency translation impact 132 (257)
End of the measurement period 3,802 4,212
Bank | International | Defined benefit pension plans | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 3,813  
End of the measurement period 3,531 3,813
Bank | International | Defined benefit pension plans | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 1,637  
End of the measurement period 1,199 1,637
Bank | International | Defined benefit pension plans | Government debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 2,176  
End of the measurement period 2,332 2,176
Bank | International | Defined benefit pension plans | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 85  
End of the measurement period 101 85
Bank | International | Defined benefit pension plans | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 20  
End of the measurement period 0 20
Bank | International | Defined benefit pension plans | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period (47)  
End of the measurement period (27) (47)
Bank | International | Defined benefit pension plans | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period (47)  
End of the measurement period (27) (47)
Bank | International | Defined benefit pension plans | Other investments, plan assets    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 77  
End of the measurement period 87 77
Bank | International | Defined benefit pension plans | Level 3    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Corporate debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Government debt securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Equity securities    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Real estate - indirect    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Hedge funds    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Other alternative investments    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Defined benefit pension plans | Level 3 | Other investments, plan assets    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0  
End of the measurement period 0 0
Bank | International | Other post-retirement defined benefit plans    
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]    
Beginning of the measurement period 0 0
Foreign currency translation impact 0 0
End of the measurement period SFr 0 SFr 0