Basis of Presentation and Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles

Standard	Date of Adoption	Description	Effect on Financial Statements or Other Significant Matters
ASU 2023-09 Income Taxes (Topic 740)	Annual periods beginning January 1, 2025 Early adoption is permitted.	This guidance requires certain annual tax disclosures related to rate reconciliation and income taxes paid. The guidance should be applied on a prospective or retrospective basis.	The guidance is not expected to have a material impact and will be incorporated into Key’s annual tax disclosures within the Form 10-K. Key is electing to use a retrospective basis.