Revenue from Contracts with Customers	3 Months Ended
Revenue from Contracts with Customers	Dec. 31, 2025
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Since net interest income on financial assets and liabilities is outside the scope of ASU No. 2014-09, Revenue from Contracts with Customers ("ASC 606"), a significant majority of Company revenues are not subject to that guidance. Revenue streams that are within the scope of ASC 606 are presented within non-interest income and are, in general, recognized as revenue at the same time the Company's obligation to the customer is satisfied. Most of the Company's customer contracts that are within the scope of ASC 606 are cancelable by either party without penalty and are short-term in nature. These sources of revenue include depositor and other consumer and business banking fees, commission income, as well as debit and credit card interchange fees. In scope revenue streams represented approximately 3.6% of Company total revenue for the three months ended December 31, 2025, compared to 3.2% for the three months ended December 31, 2024. As this standard is immaterial to the consolidated financial statements, the Company has omitted certain disclosures in ASC 606, including the disaggregation of revenue table. Sources of non-interest income within the scope of the guidance include the following: Deposit Related and Other Service Charges (recognized in Deposit fee income) - The Company's deposit accounts are governed by standardized contracts customary in the industry. Revenues are earned at a point in time or over time (monthly) from account maintenance fees and charges for specific transactions such as wire transfers, stop payment orders, overdrafts, debit card replacements, check orders and cashier’s checks. The Company’s performance obligation related to each of these fees is generally satisfied, and the related revenue recognized, at the time the service is provided (point in time or monthly). The Company is principal in each of these contracts. Debit and Credit Card Interchange Fees (recognized in Deposit fee income) - The Company receives interchange fees from the debit card or credit card payment network based on transactions involving debit or credit cards issued by the Company, generally measured as a percentage of the underlying transaction. Interchange fees from debit and credit card transactions are recognized as the transaction processing services are provided by the network. The Company acts as an agent in the card payment network arrangement, so the interchange fees are recorded net of any expenses paid to the principal (the card payment network in this case). Insurance Agency Commissions (recognized in Other income) - WAFD Insurance Group, Inc. is a wholly owned subsidiary of WaFd Bank that operates as an insurance agency, selling and marketing property and casualty insurance policies for a small number of high-quality insurance carriers. WAFD Insurance Group, Inc. earns revenue in the form of commissions paid by the insurance carriers for policies that have been sold. In addition to the origination commission, WAFD Insurance Group, Inc. may also receive contingent incentive fees based on the volume of business generated for the insurance carrier and based on policy renewal rates.

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-10

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-15

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-12

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-13

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org/606/tableOfContent

+ Details

WAFD INC 10-Q