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Period Type:	instant

Amount of accrued expenses pertaining to administrative budget accounts of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAdministrativeBudgetAccountsAccruedExpenses
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of revenue sharing contribution receivable pertaining to administrative budget accounts of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAdministrativeBudgetAccountsRevenueSharingContributionReceivables
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of administrative budget allocated to participant account under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAdministrativeBudgetAllocatedToParticipantAccount
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of contributions made for administrative budget during the period under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of decrease in administrative budget account from plan expense incurred by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAdministrativeBudgetDecreaseFromPlanExpenses
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Value of annual administrative budget per participant determined under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAnnualAdministrativeBudgetPerParticipant
Namespace Prefix:	sny_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Assumed retirement age of the participant for determination of target date fund under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanAssumedRetirementAge
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Percentage vested in eligible matching compensation contributed for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) after vesting period has been completed.

No definition available.

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

The period of service a participant must complete before becoming eligible to receive matching employer contributions under the (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanEmployeeMatchingContributionVestingPeriod
Namespace Prefix:	sny_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from true up employer contribution.

No definition available.

Name:	sny_EmployeeBenefitPlanForfeitedNonvestedAccountDecreaseFromEmployerTrueUpContribution
Namespace Prefix:	sny_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Maximum number of loans that can be outstanding at any point in time by the loans borrowed by the participants under employee benefit plan (EBP).

No definition available.

Name:	sny_EmployeeBenefitPlanNoteReceivableFromParticipantMaximumNumberOfLoansOutstanding
Namespace Prefix:	sny_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Maximum term of participant loan taken for purchase of primary residence under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanNoteReceivableFromParticipantMaximumTermForPurchaseOfPrimaryResidence
Namespace Prefix:	sny_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Term of participant loan of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanNoteReceivableFromParticipantTerm
Namespace Prefix:	sny_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The maximum percentage of after tax non-roth compensations that a participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

No definition available.

Name:	sny_EmployeeBenefitPlanParticipantContributionAfterTaxMaximumNonRothContributionPercentage
Namespace Prefix:	sny_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of annual increase of the eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanParticipantContributionAutomaticDeferralAnnualIncreasePercentage
Namespace Prefix:	sny_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Period within which the eligible participant employees can opt out from the automatic enrolled scheme under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanParticipantContributionAutomaticDeferralOptOutPeriod
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Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The maximum percentage by which a participant's contribution is automatically increased each year under the plan's escalation feature.

No definition available.

Name:	sny_EmployeeBenefitPlanParticipantContributionMaximumAutomaticDeferralAnnualIncreasePercentage
Namespace Prefix:	sny_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of participant loans transferred to (From) employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from (to) external plan.

No definition available.

Name:	sny_EmployeeBenefitPlanParticipantLoansTransferToFromPlan
Namespace Prefix:	sny_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Period over which the participants receive distribution in the form of annual recurring installments under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanPaymentForBenefitsRecurringAnnualInstallmentsPeriod
Namespace Prefix:	sny_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Value of quarterly administrative budget per participant determined under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

No definition available.

Name:	sny_EmployeeBenefitPlanQuarterlyAdministrativeBudgetPerParticipant
Namespace Prefix:	sny_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of net asset available for benefit transferred to (from) employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from (to) external plan.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule III))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 45
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477063/962-205-45-8

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

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Period Type:	duration

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanForfeitedNonvestedAccount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from employer contribution.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

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Data Type:	xbrli:monetaryItemType
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Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

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Data Type:	dtr-types:percentItemType
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Period Type:	instant

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

Name:	us-gaap-ebp_EmployeeBenefitPlanNoteReceivableFromParticipantAccountMinimumBorrowingAmount
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantContributionAutomaticDeferralRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

Name:	us-gaap-ebp_EmployeeBenefitPlanParticipantLoanInterestRate
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Name:	dei_LegalEntityAxis=sny_EBP005Member
Namespace Prefix:
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Balance Type:
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Name:	srt_StatementScenarioAxis=sny_EmployeesHiredOnOrBeforeDecember312005Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementScenarioAxis=sny_EmployeesHiredOnOrBeforeMarch312012Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementScenarioAxis=sny_EmployeesHiredOnOrAfterApril12012Member
Namespace Prefix:
Data Type:	na
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Name:	srt_RangeAxis=srt_MinimumMember
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