v3.26.1
Expected credit loss measurement - Off-balance sheet financial assets subject to ECL (Detail) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines $ 203,968 $ 267,803
Total ECL provisions (443) (347)
Total allowance and provisions (3,189) (3,058)
Guarantees    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 44,497 47,102
Total ECL provisions (76) (50)
Guarantees | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 7,140 7,388
Total ECL provisions (21) (17)
Guarantees | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,513 3,134
Total ECL provisions (41) (24)
Guarantees | of which: Financial intermediaries and hedge funds    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 26,498 29,411
Total ECL provisions (1) (1)
Guarantees | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,316 3,537
Total ECL provisions (2) (2)
Guarantees | of which: Commodity trade finance    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5 2,252
Total ECL provisions 0 (1)
Irrevocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 86,509 82,122
Total ECL provisions (293) (227)
Irrevocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 48,757 50,000
Total ECL provisions (264) (184)
Forward starting reverse repurchase and securities borrowing agreements    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 9,806 10,723
Total ECL provisions 0 0
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 54,536 119,679
Total ECL provisions (68) (67)
Decrease in committed unconditionally revocable credit lines (65,200)  
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Real estate financing    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 6,733 6,433
Total ECL provisions (4) (3)
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 9,650 11,393
Total ECL provisions (13) (15)
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 10,791 11,814
Total ECL provisions (33) (31)
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 2,146 60,500
Total ECL provisions 0 0
Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Credit cards    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 12,800 12,943
Total ECL provisions (9) (9)
Irrevocable committed prolongation of existing loans    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 8,620 8,178
Total ECL provisions (6) (3)
Twelve-month expected credit losses | Stages 1 and 2    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 193,281 258,333
Total ECL provisions (192) (184)
Total allowance and provisions (589) (576)
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 41,980 45,512
Total ECL provisions (16) (15)
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5,645 6,446
Total ECL provisions (8) (7)
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,034 2,834
Total ECL provisions (4) (5)
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees | of which: Financial intermediaries and hedge funds    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 26,224 29,288
Total ECL provisions (1) (1)
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,291 3,505
Total ECL provisions 0 0
Twelve-month expected credit losses | Stages 1 and 2 | Guarantees | of which: Commodity trade finance    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5 2,152
Total ECL provisions 0 (1)
Twelve-month expected credit losses | Stages 1 and 2 | Irrevocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 82,219 77,976
Total ECL provisions (119) (114)
Twelve-month expected credit losses | Stages 1 and 2 | Irrevocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 45,152 46,556
Total ECL provisions (98) (91)
Twelve-month expected credit losses | Stages 1 and 2 | Forward starting reverse repurchase and securities borrowing agreements    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 9,806 10,723
Total ECL provisions 0 0
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 50,673 115,982
Total ECL provisions (53) (51)
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Real estate financing    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5,461 5,291
Total ECL provisions (3) (5)
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 8,824 10,737
Total ECL provisions (8) (7)
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 10,181 11,278
Total ECL provisions (25) (24)
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 2,146 60,435
Total ECL provisions 0 0
Twelve-month expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Credit cards    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 12,158 12,361
Total ECL provisions (7) (7)
Twelve-month expected credit losses | Stages 1 and 2 | Irrevocable committed prolongation of existing loans    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 8,603 8,141
Total ECL provisions (5) (3)
Lifetime expected credit losses | Stages 1 and 2    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 9,946 8,867
Total ECL provisions (122) (115)
Total allowance and provisions (456) (428)
Lifetime expected credit losses | Stages 1 and 2 | Guarantees    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 2,348 1,448
Total ECL provisions (24) (22)
Lifetime expected credit losses | Stages 1 and 2 | Guarantees | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 1,460 916
Total ECL provisions (7) (6)
Lifetime expected credit losses | Stages 1 and 2 | Guarantees | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 392 228
Total ECL provisions (15) (15)
Lifetime expected credit losses | Stages 1 and 2 | Guarantees | of which: Financial intermediaries and hedge funds    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 254 123
Total ECL provisions 0 0
Lifetime expected credit losses | Stages 1 and 2 | Guarantees | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 1
Total ECL provisions 0 0
Lifetime expected credit losses | Stages 1 and 2 | Guarantees | of which: Commodity trade finance    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 100
Total ECL provisions 0 0
Lifetime expected credit losses | Stages 1 and 2 | Irrevocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,843 3,938
Total ECL provisions (83) (77)
Lifetime expected credit losses | Stages 1 and 2 | Irrevocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,269 3,292
Total ECL provisions (80) (72)
Lifetime expected credit losses | Stages 1 and 2 | Forward starting reverse repurchase and securities borrowing agreements    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3,739 3,449
Total ECL provisions (14) (16)
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Real estate financing    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 1,272 1,041
Total ECL provisions (1) 1
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 824 650
Total ECL provisions (4) (6)
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 498 418
Total ECL provisions (7) (7)
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 63
Total ECL provisions 0 0
Lifetime expected credit losses | Stages 1 and 2 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Credit cards    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 638 578
Total ECL provisions (2) (2)
Lifetime expected credit losses | Stages 1 and 2 | Irrevocable committed prolongation of existing loans    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 15 32
Total ECL provisions (1) 0
Lifetime expected credit losses | Stage 3    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 731 546
Total ECL provisions (125) (40)
Total allowance and provisions (1,864) (1,756)
Lifetime expected credit losses | Stage 3 | Guarantees    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 164 120
Total ECL provisions (37) (13)
Lifetime expected credit losses | Stage 3 | Guarantees | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 31 17
Total ECL provisions (6) (4)
Lifetime expected credit losses | Stage 3 | Guarantees | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 88 67
Total ECL provisions (22) (4)
Lifetime expected credit losses | Stage 3 | Guarantees | of which: Financial intermediaries and hedge funds    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 21 0
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Guarantees | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 25 31
Total ECL provisions (2) (1)
Lifetime expected credit losses | Stage 3 | Guarantees | of which: Commodity trade finance    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Irrevocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 441 174
Total ECL provisions (88) (27)
Lifetime expected credit losses | Stage 3 | Irrevocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 331 118
Total ECL provisions (82) (19)
Lifetime expected credit losses | Stage 3 | Forward starting reverse repurchase and securities borrowing agreements    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 124 248
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Real estate financing    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 101
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 1 6
Total ECL provisions 0 (2)
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 112 118
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 1
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Credit cards    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 3 4
Total ECL provisions 0 0
Lifetime expected credit losses | Stage 3 | Irrevocable committed prolongation of existing loans    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 2 5
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI)    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 10 57
Total ECL provisions (3) (9)
Total allowance and provisions (280) (298)
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 4 22
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 4 9
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 5
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees | of which: Financial intermediaries and hedge funds    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Guarantees | of which: Commodity trade finance    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Irrevocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5 35
Total ECL provisions (3) (9)
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Irrevocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 5 35
Total ECL provisions (3) (2)
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Forward starting reverse repurchase and securities borrowing agreements    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Real estate financing    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Large corporate clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: SME clients    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Lombard    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Committed unconditionally revocable credit lines / Unconditionally revocable loan commitments | of which: Credit cards    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions 0 0
Lifetime expected credit losses | Purchased credit-impaired (PCI) | Irrevocable committed prolongation of existing loans    
Disclosure Of Provision Matrix [Line Items]    
Total off-balance sheet financial instruments and other credit lines 0 0
Total ECL provisions $ 0 $ 0