BUSINESS COMBINATIONS - Narrative (Details) - USD ($) $ in Millions |
Sep. 04, 2026 |
Mar. 27, 2023 |
Sep. 30, 2026 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|---|---|---|
| Business Combination [Line Items] | |||||
| Goodwill | $ 418 | $ 346 | $ 346 | ||
| BMO Bank | |||||
| Business Combination [Line Items] | |||||
| Deposits | $ 4,861 | ||||
| Loans | 643 | ||||
| Deposit premium payment | 262 | ||||
| Goodwill | 72 | ||||
| Net assets | 190 | ||||
| BMO PSL ALLL | 5 | ||||
| ALLL for PCD loans | 1 | ||||
| BMO Bank | Core Deposits | |||||
| Business Combination [Line Items] | |||||
| Core deposit intangibles | $ 192 | ||||
| Estimated useful life | 8 years | ||||
| SVBB | Purchase Money Note | |||||
| Business Combination [Line Items] | |||||
| Debt instrument, term | 5 years | ||||
| Notes payable | $ 36,070 |
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- Definition Business Combination, Recognized Asset Acquired, Deposit Premium No definition available.
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- Definition Business Combination, Recognized Asset Acquired, Financing Receivable No definition available.
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- Definition Business Combination, Recognized Liability Assumed, Deposits No definition available.
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- Definition Weighted-average period of amortization for finite-lived intangible asset acquired in business combination, asset acquisition, and from joint venture formation, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Excludes goodwill and capitalized cost for software to be sold, leased, or marketed. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of identifiable intangible asset acquired in business combination and recognized at acquisition date. Excludes goodwill and financial asset. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of asset acquired in excess of (less than) liability assumed in business combination and recognized at acquisition date. Excludes goodwill. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Period between issuance and maturity of debt instrument, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. No definition available.
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- Definition Amount of increase in allowance for credit loss for financing receivable from purchased seasoned loan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of increase in allowance for credit loss for financing receivable purchased with credit deterioration. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after accumulated impairment loss, of asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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