v3.26.1
Asset Quality - Schedule of Performance of Loans That Have Been Modified in the Last 12 Months (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Mar. 31, 2025
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months $ 582 $ 638
Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 527 545
30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 5 59
90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 50 34
Total commercial loans    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 558 603
Total commercial loans | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 505 512
Total commercial loans | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 4 58
Total commercial loans | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 49 33
Total commercial loans | Commercial and Industrial    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 347 227
Total commercial loans | Commercial and Industrial | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 338 207
Total commercial loans | Commercial and Industrial | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 4 8
Total commercial loans | Commercial and Industrial | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 5 12
Total commercial loans | Total commercial real estate loans    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 211 376
Total commercial loans | Total commercial real estate loans | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 167 305
Total commercial loans | Total commercial real estate loans | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 50
Total commercial loans | Total commercial real estate loans | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 44 21
Total commercial loans | Commercial mortgage    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 211 327
Total commercial loans | Commercial mortgage | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 167 256
Total commercial loans | Commercial mortgage | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 50
Total commercial loans | Commercial mortgage | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 44 21
Total commercial loans | Construction    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months   49
Total commercial loans | Construction | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months   49
Total commercial loans | Construction | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months   0
Total commercial loans | Construction | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months   0
Total consumer loans    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 24 35
Total consumer loans | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 22 33
Total consumer loans | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 1 1
Total consumer loans | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 1 1
Total consumer loans | Real estate — residential mortgage    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 9 14
Total consumer loans | Real estate — residential mortgage | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 8 14
Total consumer loans | Real estate — residential mortgage | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 1 0
Total consumer loans | Real estate — residential mortgage | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 0
Total consumer loans | Home equity loans    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 8 12
Total consumer loans | Home equity loans | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 7 10
Total consumer loans | Home equity loans | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 1
Total consumer loans | Home equity loans | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 1 1
Total consumer loans | Other consumer loans    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 4 5
Total consumer loans | Other consumer loans | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 4 5
Total consumer loans | Other consumer loans | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 0
Total consumer loans | Other consumer loans | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 0
Total consumer loans | Credit cards    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 3 4
Total consumer loans | Credit cards | Current    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 3 4
Total consumer loans | Credit cards | 30-89 Days  Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months 0 0
Total consumer loans | Credit cards | 90 and Greater Days Past Due    
Financing Receivable, Past Due [Line Items]    
Total loans modified in last 12 months $ 0 $ 0