v3.26.1
REVENUE FROM CONTRACTS WITH CUSTOMERS (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers $ 141 $ 130 $ 275 $ 263
Customer-related noninterest income from other sources 41 34 79 59
Total customer-related noninterest income 182 164 354 322
Noncustomer-related noninterest income 278 26 293 39
Total noninterest income 460 190 647 361
Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 49 46 97 91
Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 36 36 70 70
Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 20 18 40 35
Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 6 2 9 12
Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 14 13 28 27
Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 16 15 31 28
Other        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 12 9 19 17
Customer-related noninterest income from other sources 8 2 9 6
Total customer-related noninterest income 20 11 28 23
Noncustomer-related noninterest income 268 19 275 28
Total noninterest income 288 30 303 51
Other | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 (1) 0 (1)
Other | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 1 (1) 0
Other | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers (1) 0 0 (1)
Other | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 1 5 3
Other | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers (1) (1) 0 1
Other | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 9 9 15 15
Zions Bank | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 41 38 81 76
Customer-related noninterest income from other sources 7 10 16 14
Total customer-related noninterest income 48 48 97 90
Noncustomer-related noninterest income (1) 1 2 1
Total noninterest income 47 49 99 91
Zions Bank | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 16 15 32 30
Zions Bank | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 12 12 25 24
Zions Bank | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 6 5 11 10
Zions Bank | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 0 1 0
Zions Bank | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 4 8 8
Zions Bank | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 2 4 4
CB&T | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 21 20 43 39
Customer-related noninterest income from other sources 12 11 25 18
Total customer-related noninterest income 33 31 68 57
Noncustomer-related noninterest income 5 1 8 3
Total noninterest income 38 32 76 60
CB&T | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 8 8 17 16
CB&T | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 5 9 9
CB&T | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 3 7 6
CB&T | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 1 1 1
CB&T | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 1 3 3
CB&T | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 2 6 4
Amegy | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 36 32 69 73
Customer-related noninterest income from other sources 9 8 21 14
Total customer-related noninterest income 45 40 90 87
Noncustomer-related noninterest income 5 3 7 5
Total noninterest income 50 43 97 92
Amegy | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 16 15 31 31
Amegy | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 8 7 15 15
Amegy | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 4 9 8
Amegy | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 0 2 8
Amegy | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 5 5 10 9
Amegy | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 2 2
NBAZ | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 11 10 21 19
Customer-related noninterest income from other sources 2 1 3 1
Total customer-related noninterest income 13 11 24 20
Noncustomer-related noninterest income 1 (1) 1 (1)
Total noninterest income 14 10 25 19
NBAZ | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 3 6 5
NBAZ | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 4 8 8
NBAZ | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 2 5 4
NBAZ | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
NBAZ | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 2 2
NBAZ | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
NSB | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 12 12 24 23
Customer-related noninterest income from other sources 1 1 2 2
Total customer-related noninterest income 13 13 26 25
Noncustomer-related noninterest income 0 0 0 0
Total noninterest income 13 13 26 25
NSB | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 3 6 6
NSB | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 4 4 8 8
NSB | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 3 3 6 6
NSB | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
NSB | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 2 4 3
NSB | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
Vectra | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 7 7 15 13
Customer-related noninterest income from other sources 1 1 2 3
Total customer-related noninterest income 8 8 17 16
Noncustomer-related noninterest income 0 3 0 3
Total noninterest income 8 11 17 19
Vectra | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 2 4 3
Vectra | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 2 2 5 5
Vectra | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 2 2
Vectra | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
Vectra | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 1 1
Vectra | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 3 2
TCBNW | Operating Segments        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 2 3 3
Customer-related noninterest income from other sources 1 0 1 1
Total customer-related noninterest income 2 2 4 4
Noncustomer-related noninterest income 0 0 0 0
Total noninterest income 2 2 4 4
TCBNW | Operating Segments | Commercial account fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 1 1 1 1
TCBNW | Operating Segments | Card fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 1 1 1
TCBNW | Operating Segments | Retail and business banking fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
TCBNW | Operating Segments | Capital markets fees and income        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
TCBNW | Operating Segments | Wealth management fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers 0 0 0 0
TCBNW | Operating Segments | Other customer-related fees        
Segment Reporting [Line Items]        
Total noninterest income from contracts with customers $ 0 $ 0 $ 1 $ 1