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Business Combinations - Pro Forma (Details) - Columbia Banking Systems and Pacific Premier Bancorp Merger - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Business Combination [Line Items]
Net interest income	$ 626	$ 619	$ 1,840	$ 1,882
Non-interest income	90	85	260	224
Net income (1)	242	$ 215	618	455
Business Combination, Acquisition Related Costs - Combined for proforma	$ (135)		$ (161)	$ 161

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