Other Financial Assets - Summary of Changes in Allowance for Impairment Losses (Detail) - Other financial assets [member] - JPY (¥) ¥ in Millions	12 Months Ended
Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2024
Disclosure of Doubtful Accounts for Other Financial Assets [line items]
Balance at beginning of year	¥ 2,513	¥ 2,748	¥ 2,988
Remeasurement	178	18	97
Write-offs	(284)	(253)	(345)
Exchange differences on translating foreign operations	2	0	8
Balance at end of year	¥ 2,409	¥ 2,513	¥ 2,748

Additional allowance recognised in profit or loss, allowance for credit losses of financial assets.

No definition available.

Name:	hmc_AdditionalAllowanceRecognisedInProfitOrLossAllowanceForCreditLossesOfFinancialAssets
Namespace Prefix:	hmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

Allowance account for impairment losses of financial assets beginning balance.

No definition available.

Name:	hmc_AllowanceAccountForImpairmentLossesOfFinancialAssetsBeginningBalance
Namespace Prefix:	hmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Allowance account for impairment losses of financial assets ending balance.

No definition available.

Name:	hmc_AllowanceAccountForImpairmentLossesOfFinancialAssetsEndingBalance
Namespace Prefix:	hmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Disclosure of Doubtful Accounts for Other Financial Assets [line items]

No definition available.

Name:	hmc_DisclosureOfDoubtfulAccountsForOtherFinancialAssetsLineItems
Namespace Prefix:	hmc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Increase (decrease) through net exchange differences, allowance for credit losses of financial assets.

No definition available.

Name:	hmc_IncreaseDecreaseThroughNetExchangeDifferencesAllowanceForCreditLossesOfFinancialAssets
Namespace Prefix:	hmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Utilisation, allowance for credit losses of financial assets.

No definition available.

Name:	hmc_UtilisationAllowanceForCreditLossesOfFinancialAssets
Namespace Prefix:	hmc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	ifrs-full_ClassesOfFinancialAssetsAxis=hmc_OtherFinancialAssetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: