CECL (Details 2) - CHF (SFr)
SFr in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance SFr 1,536 SFr 1,049  
Allowance for loan losses, Beginning Balance   946 SFr 902
Current-period provision for expected credit losses 25 900  
of which methodology change (1) (19)  
of which provisions for interest 48 37  
Net movements recognized in statements of operations     284
Gross write-offs (297) (325) (299)
Recoveries 14 13 25
Net write-offs (283) (312)  
Net write-offs, loans     (274)
Provisions for interest     42
Foreign currency translation impact and other adjustments, net 19 (101)  
Foreign currency translation impact and other adjustments, loans, net     (8)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 1,297 1,536 1,049
Allowance for loan losses, Ending Balance     946
of which individually evaluated 785 866 609
of which collectively evaluated 512 670 337
Loans held at amortized cost      
Purchases 4,383 2,801 2,496
Reclassifications from loans held-for-sale 133 6 11
Reclassifications to loans held-for-sale 4,780 2,025 3,138
Sales 4,442 1,644 3,001
Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   103  
Corporate and institutional      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance 1,218 808  
Allowance for loan losses, Beginning Balance   760 715
Current-period provision for expected credit losses (53) 709  
of which methodology change (1) (19)  
of which provisions for interest 23 15  
Net movements recognized in statements of operations     221
Gross write-offs (242) (238) (213)
Recoveries 5 5 16
Net write-offs (237) (233)  
Net write-offs, loans     (197)
Provisions for interest     28
Foreign currency translation impact and other adjustments, net 12 (66)  
Foreign currency translation impact and other adjustments, loans, net     (7)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 940 1,218 808
Allowance for loan losses, Ending Balance     760
of which individually evaluated 512 636 464
of which collectively evaluated 428 582 296
Loans held at amortized cost      
Purchases 4,361 2,756 2,478
Reclassifications from loans held-for-sale 133 6 11
Reclassifications to loans held-for-sale 4,780 2,007 3,138
Sales 4,442 1,626 3,001
Corporate and institutional | Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   48  
Consumer      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance 318 241  
Allowance for loan losses, Beginning Balance   186 187
Current-period provision for expected credit losses 78 191  
of which methodology change 0 0  
of which provisions for interest 25 22  
Net movements recognized in statements of operations     63
Gross write-offs (55) (87) (86)
Recoveries 9 8 9
Net write-offs (46) (79)  
Net write-offs, loans     (77)
Provisions for interest     14
Foreign currency translation impact and other adjustments, net 7 (35)  
Foreign currency translation impact and other adjustments, loans, net     (1)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 357 318 241
Allowance for loan losses, Ending Balance     186
of which individually evaluated 273 230 145
of which collectively evaluated 84 88 41
Loans held at amortized cost      
Purchases 22 45 18
Reclassifications from loans held-for-sale 0 0 0
Reclassifications to loans held-for-sale 0 18 0
Sales 0 18 0
Consumer | Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   55  
Bank      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance 1,535 1,048  
Allowance for loan losses, Beginning Balance   945 901
Current-period provision for expected credit losses 25 900  
of which methodology change (1) (19)  
of which provisions for interest 48 37  
Net movements recognized in statements of operations     284
Gross write-offs (297) (325) (299)
Recoveries 14 13 25
Net write-offs (283) (312)  
Net write-offs, loans     (274)
Provisions for interest     42
Foreign currency translation impact and other adjustments, net 19 (101)  
Foreign currency translation impact and other adjustments, loans, net     (8)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 1,296 1,535 1,048
Allowance for loan losses, Ending Balance     945
of which individually evaluated 785 865 608
of which collectively evaluated 511 670 337
Loans held at amortized cost      
Purchases 4,383 2,801 2,496
Reclassifications from loans held-for-sale 133 6 11
Reclassifications to loans held-for-sale 4,780 2,025 3,138
Sales 4,442 1,644 3,001
Bank | Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   103  
Bank | Corporate and institutional      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance 1,217 807  
Allowance for loan losses, Beginning Balance   759 714
Current-period provision for expected credit losses (53) 709  
of which methodology change (1) (19)  
of which provisions for interest 23 15  
Net movements recognized in statements of operations     221
Gross write-offs (242) (238) (213)
Recoveries 5 5 16
Net write-offs (237) (233)  
Net write-offs, loans     (197)
Provisions for interest     28
Foreign currency translation impact and other adjustments, net 12 (66)  
Foreign currency translation impact and other adjustments, loans, net     (7)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 939 1,217 807
Allowance for loan losses, Ending Balance     759
of which individually evaluated 512 635 463
of which collectively evaluated 427 582 296
Loans held at amortized cost      
Purchases 4,361 2,756 2,478
Reclassifications from loans held-for-sale 133 6 11
Reclassifications to loans held-for-sale 4,780 2,007 3,138
Sales 4,442 1,626 3,001
Bank | Corporate and institutional | Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   48  
Bank | Consumer      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Loans Held at Amortized Cost, Allowance for Credit Losses, Beginning Balance 318 241  
Allowance for loan losses, Beginning Balance   186 187
Current-period provision for expected credit losses 78 191  
of which methodology change 0 0  
of which provisions for interest 25 22  
Net movements recognized in statements of operations     63
Gross write-offs (55) (87) (86)
Recoveries 9 8 9
Net write-offs (46) (79)  
Net write-offs, loans     (77)
Provisions for interest     14
Foreign currency translation impact and other adjustments, net 7 (35)  
Foreign currency translation impact and other adjustments, loans, net     (1)
Loans Held at Amortized Cost, Allowance for Credit Losses, Ending Balance 357 318 241
Allowance for loan losses, Ending Balance     186
of which individually evaluated 273 230 145
of which collectively evaluated 84 88 41
Loans held at amortized cost      
Purchases 22 45 18
Reclassifications from loans held-for-sale 0 0 0
Reclassifications to loans held-for-sale 0 18 0
Sales SFr 0 18 SFr 0
Bank | Consumer | Cumulative Effect, Period of Adoption, Adjustment [Member]      
Loans Held At Amortized Cost, Allowance for Credit Losses [Roll Forward]      
Current-period provision for expected credit losses   SFr 55