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Asset Quality - Schedule of Performance of Loans That Have Been Modified in the Last 12 Months (Details) - USD ($) $ in Millions | Jun. 30, 2026 | Jun. 30, 2025
--- | --- | ---
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | $ 532 | $ 516
Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 463 | 426
30-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 16 | 65
90 and Greater Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 53 | 25
Total commercial loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 508 | 480
Total commercial loans | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 441 | 393
Total commercial loans | 30-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 14 | 63
Total commercial loans | 90 and Greater Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 53 | 24
Total commercial loans | Commercial and Industrial |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 388 | 165
Total commercial loans | Commercial and Industrial | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 365 | 149
Total commercial loans | Commercial and Industrial | 30-89 Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 14 | 13
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 | 9 | 3
Total commercial loans | Total commercial real estate loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 120 | 315
Total commercial loans | Total commercial real estate loans | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 76 | 244
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 | 120 | 281
Total commercial loans | Commercial mortgage | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 76 | 210
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 |  | 34
Total commercial loans | Construction | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months |  | 34
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 | 36
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 | 2 | 2
Total consumer loans | 90 and Greater Days Past Due |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 0 | 1
Total consumer loans | Real estate — residential mortgage |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 10 | 16
Total consumer loans | Real estate — residential mortgage | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 9 | 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 | 2
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 | 9 | 11
Total consumer loans | Home equity loans | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 8 | 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 | 1 | 0
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 | 0 | 1
Total consumer loans | Other consumer loans |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 3 | 5
Total consumer loans | Other consumer loans | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 3 | 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 | 2 | 4
Total consumer loans | Credit cards | Current |  |
Financing Receivable, Past Due [Line Items] |  |
Total loans modified in last 12 months | 2 | 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

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