Document and Entity Information [Abstract] Document Information [Table] Legal Entity [Axis] Entity [Domain] Represents the information pertaining to EBP 005 plan. E B P 005 [Member] U.S. Group Savings Plan Document Information [Line Items] Document Type Entity Registrant Name Entity Central Index Key Amendment Flag Statements of Net Assets Available for Benefits EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Asset [Abstract] ASSETS EBP, Investment, Fair Value [Abstract] Investments EBP, Investment, Plan Interest in Master Trust, Fair and Contract Value Plan interest in the Sanofi U.S. Group Savings Master Trust (Note 3) EBP, Investment, Fair and Contract Value Total investments EBP, Receivable [Abstract] Receivables EBP, Participant Contribution, Receivable Contributions receivable from participating employees EBP, Employer Contribution, Receivable Contributions receivable from employer EBP, Other Receivable Other receivable EBP, Note Receivable from Participant Notes receivable from participants Participant Loans EBP, Receivable Total receivables EBP, Asset Total Assets EBP, Liability [Abstract] LIABILITIES EBP, Accrued Expense Accrued administrative expenses EBP, Net Asset Available for Benefit End of year Beginning of year Net assets available for benefits Statement of Change in Net Asset Available for Benefit EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Change in Net Asset Available for Benefit, Increase [Abstract] ADDITIONS TO NET ASSETS ATTRIBUTED TO EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Employee EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash Employer EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Rollover EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment [Abstract] Investment income EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Net investment income from Sanofi U.S. Group Savings Master Trust Net investment income EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Interest on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase Total additions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] DEDUCTIONS FROM NET ASSETS ATTRIBUTED TO EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Distributions EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Fees and administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease Total deductions EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Increase in net assets available for benefits EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan Transfer out (see Note1) Transfer out of plan EBP, Net Asset Available for Benefit [Abstract] NET ASSETS AVAILABLE FOR BENEFITS Net Assets: Description of the Plan EBP, Description of Plan [Table] EBP, Description of Plan [Line Items] Description of the Plan Termination of the Plan EBP, Description of Plan [Text Block] Description of the Plan Summary of Significant Accounting Policies EBP, Accounting Policy [Table] EBP, Accounting Policy [Line Items] Summary of Significant Accounting Policies EBP, Summary of Accounting Policy [Text Block] Summary of Significant Accounting Policies Investment in Master Trust EBP, Master Trust [Table] EBP, Master Trust [Line Items] Investment in Master Trust EBP, Master Trust [Text Block] Investment in Master Trust Related Party and Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Line Items] Related Party and Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Text Block] Related Party and Party-in-Interest Transactions No definition available. Termination of the Plan EBP, Plan Termination [Text Block] Termination of the Plan Subsequent Events EBP, Subsequent Event [Table] EBP, Subsequent Event [Line Items] Subsequent Events EBP, Subsequent Event [Text Block] Subsequent Events Schedule H, Line 4i - Schedule of Assets (Held at End of Year) EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Text Block] Schedule H, Line 4i - Schedule of Assets (Held at End of Year) EBP, Basis of Accounting [Policy Text Block] Basis of Accounting EBP, Use of Estimate [Policy Text Block] Use of Estimates EBP, Investment [Policy Text Block] Investment Valuation EBP, Note Receivable from Participant [Policy Text Block] Notes Receivable from Participants EBP, Payment to Participant [Policy Text Block] Payment of Benefits EBP, Expense [Policy Text Block] Fees and Administrative Expenses EBP, Risk and Uncertainty [Policy Text Block] Risks and Uncertainties EBP, Master Trust [Table Text Block] Investments and other assets and changes in net assets of Master trust EBP, Investment, Fair Value and NAV [Table Text Block] Schedule of Master Trust assets at fair value Tabular disclosure of investments measured at net asset value. Employee Benefit Plan, Investments at Net Asset Value [Table Text Block] Schedule of investments measured at NAV EBP, Fully Benefit-Responsive Investment Contract [Table Text Block] Schedule of types of investment contracts held by the Master Trust Statistical Measurement [Axis] Statistical Measurement [Domain] Minimum [Member] Minimum Maximum [Member] Maximum Scenario [Axis] Scenario [Domain] Represents information pertaining to participants hired on or before December 31, 2005. Employees Hired On Or Before December 31, 2005 [Member] Employees hired on or before December 31, 2005 Represents information pertaining to participants hired on or after January 1, 2006. Employees Hired On Or After January 1, 2006 [Member] Employees hired on or after January 1, 2006 Represents information pertaining to participants hired on or after March 31, 2012. Employees Hired On Or Before March 31, 2012 [Member] Employees hired on or before March 31, 2012 Represents information pertaining to participants hired on or after April 1, 2012. Employees Hired On Or After April 1, 2012 [Member] Employees hired on or after April 1, 2012 Amount of participant loans transferred to (From) employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from (to) external plan. Employee Benefit Plan, Participant Loans, Transfer To (From) Plan Participant loan transfer out EBP, Participant Contribution, Automatic, Deferral Rate Automatic deferral rate 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)). Employee Benefit Plan, Participant Contribution, Automatic Deferral, Opt Out, Period Opt out period 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)). Employee Benefit Plan, Participant Contribution, Automatic Deferral, Annual Increase, Percentage Automatic deferral, annual increase The maximum percentage by which a participant's contribution is automatically increased each year under the plan's escalation feature. Employee Benefit Plan, Participant Contribution, Maximum Automatic Deferral, Annual Increase, Percentage Automatic deferral, maximum annual increase EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage Maximum participant contribution, percentage 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. Employee Benefit Plan, Participant Contribution, After Tax, Maximum Non Roth Contribution, Percentage Maximum non-roth contribution, percentage EBP, Employer Contribution, Matching Percentage Employer contribution EBP, Employer Contribution, Participant Compensation Matched, Percentage Percentage of participant eligible compensation Assumed retirement age of the participant for determination of target date fund under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Assumed Retirement Age Assumed retirement age 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. Employee Benefit Plan, Employee Matching Contribution, Vesting Percentage Vesting percentage The period of service a participant must complete before becoming eligible to receive matching employer contributions under the (employee benefit plan (EBP)). Employee Benefit Plan, Employee Matching Contribution, Vesting Period Vesting period EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount Note receivable, minimum borrowing amount EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage Note receivable, maximum borrowing percentage EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount Note receivable, maximum borrowing amount EBP, Asset Held for Investment, Participant Loan, Interest Rate Participant Loans, Interest Rates (in %) Term of participant loan of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Note Receivable From Participant, Term Loan term 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). Employee Benefit Plan, Note Receivable From Participant, Maximum Number Of Loans, Outstanding Number of loans outstanding Maximum term of participant loan taken for purchase of primary residence under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Note Receivable From Participant, Maximum Term For Purchase Of Primary Residence Maximum term for purchase of primary residence 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)). Employee Benefit Plan, Payment For Benefits, Recurring Annual Installments, Period Annual installment payment period EBP, Forfeited Nonvested Account Forfeited non-vested accounts EBP, Forfeited Nonvested Account, Decrease from Employer Contribution Amount of forfeited nonvested accounts used to offset employer contributions Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from true up employer contribution. Employee Benefit Plan, Forfeited Nonvested Account, Decrease From Employer True Up Contribution Amount of forfeited nonvested accounts used to offset employer true up contributions Value of quarterly administrative budget per participant determined under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Quarterly Administrative Budget Per Participant Quarterly administrative budget per participant Value of annual administrative budget per participant determined under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Annual Administrative Budget Per Participant Annual administrative budget per participant Amount of contributions made for administrative budget during the period under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget, Contribution Administrative budget contribution Amount of decrease in administrative budget account from plan expense incurred by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget, Decrease From Plan Expenses Amount of administrative budget used for plan expenses Amount of administrative budget allocated to participant account under employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget, Allocated To Participant Account Amount of administrative budget allocated to plan participants Carrying amount as of the balance sheet date of the administrative budget accounts of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget Accounts Administrative budget account balance Amount of revenue sharing contribution receivable pertaining to administrative budget accounts of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget Accounts, Revenue Sharing Contribution, Receivables Administrative budget account receivables Amount of accrued expenses pertaining to administrative budget accounts of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Administrative Budget Accounts, Accrued Expenses Administrative budget account, accrued expenses EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Axis] EBP, Nonconsolidated, Master Trust and Plan Interest in Master Trust [Domain] EBP, Nonconsolidated, Master Trust [Member] Sanofi U.S. Group Savings Master Trust EBP, Nonconsolidated, Plan Interest in Master Trust [Member] Sanofi U.S. Group Savings Plan's Interest in Sanofi U.S. Group Savings Master Trust Investment Type [Axis] Investments [Domain] EBP, Self-Directed Brokerage Account [Member] Self-directed brokerage accounts Common Collective Trust [Member] Common collective trust funds Equity Funds [Member] Domestic equities EBP, Traditional Guaranteed Investment Contract [Member] Fixed income securities EBP, Employer, Common Stock [Member] Common stock EBP, Investment, Fair Value Total investments at fair value Total investments measured at fair value EBP, Investment, Contract Value [Abstract] Investments at contract value EBP, Investment, Contract Value Stable value fund EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Net Appreciation in the value of investments EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment Dividend income EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Investment Interest Amount of increase in net asset available for benefit after transfers to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Employee Benefit Plan, Change in Net Asset Available for Benefit, Increase after Transfers Increase in Net Assets Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Total investments in the fair value hierarchy Fair Value, Inputs, Level 1 [Member] Level 1 Fair Value Measured at Net Asset Value Per Share [Member] Investments measured at net asset value Represents the information pertaining to US Treasury Money Market Trust. US Treasury Money Market Trust [Member] US Treasury Money Market Trust Represents the information pertaining to Sanofi U.S. Active Bond Fund. Sanofi U.S. Active Bond Fund [Member] Sanofi U.S. Active Bond Fund Represents the information pertaining to Sanofi U.S. Bond Fund Index. Sanofi U.S. Bond Fund Index [Member] Sanofi U.S. Bond Fund Index Represents the information pertaining to Sanofi International Stock Index. Sanofi International Stock Index [Member] Sanofi International Stock Index Represents the information pertaining to Sanofi U.S. Active Stock Fund. Sanofi U.S. Active Stock Fund [Member] Sanofi U.S. Active Stock Fund Represents the information pertaining to Sanofi U.S. Stock Index. Sanofi U.S. Stock Index [Member] Sanofi U.S. Stock Index Represents the information pertaining to Sanofi-Aventis International Core Fund . Sanofi-Aventis International Core Fund [Member] Sanofi-Aventis International Core Fund Represents the information pertaining to TRP Retirement Date Trusts . TRP Retirement Date Trusts [Member] TRP Retirement Date Trusts EBP, Fair Value, Investment, NAV, Redemption, Notice Period Redemption Notice Period Represents the information pertaining to cash reserves common trust fund. Employee Benefit Plan, Cash Reserves Common Trust Fund [Member] Cash reserves common trust fund EBP, Synthetic Investment Contract [Member] Synthetic investment contracts Represents the average crediting rate for fully benefit-responsive investment contracts. Employee Benefit Plan, Fully Benefit-Responsive Investment Contract, Crediting Rate Average crediting rate for the investment contracts Represents the redemption notice period for Employee Benefit Plan, Fully Benefit-Responsive Investment Contract, Redemption Notice Period Redemption notice period (in years) Income Tax Status EBP, Tax Status [Table] EBP, Tax Status [Line Items] Income Tax Status EBP, Tax Determination Letter, Obtained [true false] Determination letter obtained EBP, Tax Determination Letter, Date Determination letter date EBP, Tax Qualification Status [Extensible Enumeration] Tax qualification status EBP, Related Party and Party-in-Interest [Axis] EBP, Related Party and Party-in-Interest [Domain] Represents information pertaining to master trust. Employee Benefit Plan, Master Trust [Member] Master trust Represents information pertaining to employer. Employee Benefit Plan, Participants [Member] Participants EBP, Investment Acquired, Excluding Plan Interest in Master Trust, Cost Purchases EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price Sales EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Realized Gain (Loss) on Investment Realized gains EBP, Investment, Number of Shares Total shares EBP, Investment, Plan Interest in Master Trust, Fair Value Market value of shares Represents the percentage of vesting of participant accounts in the event of termination. Employee Benefit Plan, Vesting Percentage in Event of Termination Vesting percentage EBP, Asset Held for Investment, Plan Interest in Master Trust, Current Value Sanofi U.S. Group Savings Master Trust EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Participant Loans EBP, Asset Held for Investment, Party-in-Interest [true false] EBP, Asset Held for Investment, Plan Interest in Master Trust, Participation Status [Extensible Enumeration]