The maximum percentage of debt instrument not protected with hedge contract.

No definition available.

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Namespace Prefix:	csan_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of categories of customers in credit risk of lease receivables.

+ References

No definition available.

+ Details

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Namespace Prefix:	csan_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of reasonably possible increase (decrease) in associated risk variables in financial instruments.

+ References

No definition available.

+ Details

Name:	csan_PercentageOfReasonablyPossibleIncreaseDecreaseInAssociatedRiskVariables
Namespace Prefix:	csan_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of purchase commitments.

+ References

No definition available.

+ Details

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

- Definition

The description of how the entity establishes the hedge ratio and what are the sources of hedge ineffectiveness. Hedge ratio is the relationship between the quantity of the hedging instrument and the quantity of the hedged item in terms of their relative weighting. [Refer: Gain (loss) on hedge ineffectiveness]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2021-01-01
-Paragraph 22B
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2021-en-r&anchor=para_22B_c&doctype=Standard
-URIDate 2021-03-24

+ Details

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

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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

- Details

Name:	srt_StatementScenarioAxis=csan_ScenarioOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=csan_ScenarioTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	ifrs-full_BorrowingsByNameAxis=csan_BrazilianNationalEconomicAndSocialDevelopmentBankProjectEightMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ProductsAndServicesAxis=ifrs-full_ElectricityDistributionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_SignificantInvestmentsInSubsidiariesAxis=csan_CompassGasEEnergiaSAMember
Namespace Prefix:
Data Type:	na
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Financial Assets and Liabilities - Derivative financial instruments, interset rate and credit risk - Additional information (Detail) R$ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2021	Dec. 31, 2021 BRL (R$) Item
Disclosure of detailed information about financial instruments [line items]
Description of how entity establishes hedge ratio and what sources of hedge ineffectiveness are		The Company established a 1:1 hedge ratio for hedge relationships, since the underlying risk of the interest rate and exchange rate swap is identical to the hedged risk component
Number of categories of customers in credit risk of lease receivables \| Item		2
Variation scenario +/- 25%
Disclosure of detailed information about financial instruments [line items]
Percentage of reasonably possible increase (decrease) in associated risk variables		25.00%
Variation scenario +/- 50%
Disclosure of detailed information about financial instruments [line items]
Percentage of reasonably possible increase (decrease) in associated risk variables		50.00%
Comgas [member] \| BNDES Project VIII
Disclosure of detailed information about financial instruments [line items]
Maximum percentage of debt instrument not protected	3.00%
Electricity trading [member]
Disclosure of detailed information about financial instruments [line items]
Purchase commitment		R$ 0
Electricity trading [member] \| Compass Gás e Energia [member]
Disclosure of detailed information about financial instruments [line items]
Purchase commitment		R$ 0