XML 173 R130.htm IDEA: XBRL DOCUMENT
v3.25.4

Employee Benefits - Additional Information (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2026 | Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Age of employees under condition one |  | 55 years |  |
Period of service under condition one |  | 5 years |  |
Age of employees under condition two |  | 50 years |  |
Period of service under condition two |  | 15 years |  |
Minimum period of service at the time of termination hired before 2001 |  | 15 years |  |
Settlement loss |  | $ 0 | $ 0 |
Percentage increase or decrease in expected return on plan assets |  | 0.25% |  |
Estimated increase or decrease in net pension cost |  | $ 2,000,000 |  |
Percentage increase or decrease in assumed discount rate |  | 0.25% |  |
Estimated change in net pension cost due to discount rate |  | $ 1,000,000 |  |
Expected return on plan assets on estimating 2025 pension cost |  | 5.25% |  |
Employer contribution to saving plan |  | 7.00% | 7.00% |
Employer discretionary contribution, required service period |  | 1 year |  |
Total expenses associated with saving plan |  | $ 132,000,000 | $ 145,000,000 | $ 99,000,000
Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Employees contribution to saving plan |  | 1.00% |  |
Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Employees contribution to saving plan |  | 100.00% |  |
Pension Plans |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Net periodic benefit cost (credit) |  | $ 7,000,000 | $ 11,000,000 | $ 30,000,000
Expected return on plan assets |  | 5.25% | 5.25% | 4.50%
Pension Plans | Forecast |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Net periodic benefit cost (credit) | $ 9,000,000 |  |  |
Postretirement Benefit Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Net periodic benefit cost (credit) |  | $ (2,000,000) | $ (2,000,000) | $ (2,000,000)
Postretirement Benefit Plan | Forecast |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Net periodic benefit cost (credit) | $ (2,000,000) |  |  |

X
- Definition Age of employees under condition one. + References No definition available. + Details
Name: | key_AgeOfEmployeesUnderConditionOne
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Age of employees under condition two. + References No definition available. + Details
Name: | key_AgeOfEmployeesUnderConditionTwo
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-Term Rate of Return on Plan Assets, Year-End Liability + References No definition available. + Details
Name: | key_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermRateOfReturnOnPlanAssetsYearEndLiability
Namespace Prefix: | key_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Defined Contribution Plan, Employer Discretionary Contribution, Required Service Period + References No definition available. + Details
Name: | key_DefinedContributionPlanEmployerDiscretionaryContributionRequiredServicePeriod
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated Change In Net Pension Cost Due To Discount Rate + References No definition available. + Details
Name: | key_EstimatedChangeInNetPensionCostDueToDiscountRate
Namespace Prefix: | key_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Estimated Increase Or Decrease In Net Pension Cost + References No definition available. + Details
Name: | key_EstimatedIncreaseOrDecreaseInNetPensionCost
Namespace Prefix: | key_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Expected Return On Plan Assets On Estimating One Year Pension Cost + References No definition available. + Details
Name: | key_ExpectedReturnOnPlanAssetsOnEstimatingOneYearPensionCost
Namespace Prefix: | key_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum period of service at the time of termination hired before 2001. + References No definition available. + Details
Name: | key_MinimumPeriodOfServiceAtTimeOfTerminationHiredBeforeTwoThousandOne
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Increase Or Decrease In Assumed Discount Rate + References No definition available. + Details
Name: | key_PercentageIncreaseOrDecreaseInAssumedDiscountRate
Namespace Prefix: | key_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage Increase Or Decrease In Expected Return On Plan Assets + References No definition available. + Details
Name: | key_PercentageIncreaseOrDecreaseInExpectedReturnOnPlanAssets
Namespace Prefix: | key_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of service under condition one. + References No definition available. + Details
Name: | key_PeriodOfServiceUnderConditionOne
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of service under condition two. + References No definition available. + Details
Name: | key_PeriodOfServiceUnderConditionTwo
Namespace Prefix: | key_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (k) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (l) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (j)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (c)(iv)(02) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (c)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-7 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (m) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (q) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-17 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-6 + Details
Name: | us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (m) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(10) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanSettlementsBenefitObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 70 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480794/715-70-50-1 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |