Name:	ifrs-full_DisclosureOfFinancialInstrumentsLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The amount of loans and advances the entity has made to customers.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
-Number 1
-IssueDate 2025-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard
-URIDate 2025-03-27

Name:	ifrs-full_LoansAndAdvancesToCustomers
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Allowance accounts for credit losses of financial assets.

No definition available.

Name:	smfg_AllowanceAccountsForCreditLossesOfFinancialAssets
Namespace Prefix:	smfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Required ratio of capital conservation buffer on full implementation in addition to Common Equity Tier 1 Capital ratio.

No definition available.

Name:	smfg_CapitalConservationBuffer
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Countercyclical buffer.

No definition available.

Name:	smfg_CountercyclicalBuffer
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Countercyclical buffer percentage.

No definition available.

Name:	smfg_CountercyclicalBufferPercentage
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Demand deposits maturity period.

No definition available.

Name:	smfg_DemandDepositsMaturityPeriod
Namespace Prefix:	smfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Required ratio of Global Systemically Important Bank ("G-SIB") surcharge on full implementation in addition to Common Equity Tier 1 Capital ratio.

No definition available.

Name:	smfg_GSIBCapitalSurcharge
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Increase (decrease) in allowance accounts for credit losses of financial assets.

No definition available.

Name:	smfg_IncreaseDecreaseInAllowanceAccountsForCreditLossesOfFinancialAssets
Namespace Prefix:	smfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The minimum Common Equity Tier1 Capital Ratio (Common Equity Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

No definition available.

Name:	smfg_MinimumCommonEquityRequirement
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The minimum Tier 1 Capital Ratio (Tier one capital divided by risk-weighted assets) phase-in arrangements required for capital adequacy purposes under the regulatory framework for prompt corrective action.

No definition available.

Name:	smfg_MinimumTierOneCapitalRequirement
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Ratio of decline in the economic value of equity to Tier 1 capital.

No definition available.

Name:	smfg_RatioOfEconomicValueOnEquityToTierOneCapital
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Strategic equity investments permitted percentage of reduction.

No definition available.

Name:	smfg_StrategicEquityInvestmentsPermittedPercentageOfReduction
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The threshold percentage of changes in economic value on equity to Tier1 capital ratio in the interest rate risk in the banking book framework.

No definition available.

Name:	smfg_ThresholdPercentageOfFinancialServiceAgency
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The minimum capital ratio (capital ratio divided by risk-weighted assets) on full implementation required for capital adequacy purposes under the regulatory framework for prompt corrective action.

No definition available.

Name:	smfg_TotalCapitalRequirement
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Confidence interval percentage.

No definition available.

Name:	smfg_ValueAtRiskConfidenceInterval
Namespace Prefix:	smfg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Value at risk holding period.

No definition available.

Name:	smfg_ValueAtRiskHoldingPeriod
Namespace Prefix:	smfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Value at risk observation period.

No definition available.

Name:	smfg_ValueAtRiskObservationPeriod
Namespace Prefix:	smfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Name:	ifrs-full_ClassesOfFinancialInstrumentsAxis=smfg_ModifiedLoansAndAdvancesSubjectToLifetimeECLMeasurementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis=smfg_LifetimeEclCreditImpairedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_RangeAxis=ifrs-full_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_CapitalRequirementsAxis=smfg_BeforeAdoptionOfBaselIIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_CapitalRequirementsAxis=smfg_BaselIIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=smfg_SumitomoMitsuiBankingCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: