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Business Combinations - Narrative (Details)	Aug. 31, 2025 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Business Combination [Line Items]
Goodwill		$ 1,481,000,000	$ 1,029,000,000
Finite-Lived Intangible Asset, Useful Life		10 years
Columbia Banking Systems and Pacific Premier Bancorp Merger
Business Combination [Line Items]
Total purchase price consideration	$ 2,355,000,000
Business Acquisition, Equity Interest Issued or Issuable, Share Exchange Ratio	0.9150
Goodwill	$ 452,000,000
Business Combination, Goodwill, Expected Tax Deductible, Amount	0
Business Combination, Acquired Receivable, Purchased without Credit Deterioration, Fair Value	11,400,000,000
Fair value of PCD loans	$ 404,000,000
Finite-Lived Intangible Asset, Useful Life	10 years

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