Provisioned amount, monetary restatement.

No definition available.

Name:	csan_OtherProvisionsMonetaryRestatment
Namespace Prefix:	csan_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Provisioned amount, principal.

+ References

No definition available.

+ Details

Name:	csan_OtherProvisionsPrincipalAmount
Namespace Prefix:	csan_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of monetary restatement of receivables from taxes other than income tax.

+ References

No definition available.

+ Details

Name:	csan_ReceivablesFromTaxesOtherThanIncomeTaxMonetaryRestatement
Namespace Prefix:	csan_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The principal amount of receivables from taxes other than income tax.

+ References

No definition available.

+ Details

Name:	csan_ReceivablesFromTaxesOtherThanIncomeTaxPrincipalAmount
Namespace Prefix:	csan_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Trade and other current receivables.

+ References

No definition available.

+ Details

Name:	csan_TradeAndOtherCurrentReceivablesLineItems
Namespace Prefix:	csan_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of provisions other than provisions for employee benefits. [Refer: Provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 37
-IssueDate 2021-01-01
-Paragraph 84
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2021-en-r&anchor=para_84_a&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 78
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_78_d&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_OtherProvisions
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of receivables from taxes other than income tax. Income taxes include all domestic and foreign taxes that are based on taxable profits. Income taxes also include taxes, such as withholding taxes, that are payable by a subsidiary, associate or joint arrangement on distributions to the reporting entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 78
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2021-03-24

+ Details

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

- Details

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

- Details

Name:	srt_LitigationCaseAxis=csan_PisAndCofinsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=ifrs-full_ProvisionForTaxesOtherThanIncomeTaxMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Other Tax Receivables - Additional Information (Detail) - BRL (R$) R$ in Thousands	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Trade and Other Current Receivables [line items]
Receivables from taxes other than income tax	R$ 2,801,167		R$ 1,743,038
Comgas [member] \| PIS and COFINS [member]
Trade and Other Current Receivables [line items]
Receivables from taxes other than income tax	956,338	R$ 957,663
Principal amount	563,175	573,462
Monetary restatement	393,213	R$ 382,201
Comgas [member] \| PIS and COFINS [member] \| Provision for uncertain tax liabilities [member]
Trade and Other Current Receivables [line items]
Provisioned amount	638,975
Provisioned amount, principal	375,565
Provisioned amount, monetary restatement	R$ 263,410