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v3.22.1

The quantitative sensitivity analysis for significant assumptions for the post-employment health benefit as of December 31, 2021, is shown below: (Details) - Healthcare Plan [Member] R$ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 BRL (R$) shares
Possible Increase In Actuarial Assumption [Member] | Actuarial assumption of discount rates [member] |
IfrsStatementLineItems [Line Items] |
Sensitivity level | 0.50%
Effect on current service cost and on interest on actuarial obligations | R$ | R$ 559
Effect on present value of obligations | shares | (20,842)
Possible Increase In Actuarial Assumption [Member] | Actuarial Assumption Of Medical Inflation [Member] |
IfrsStatementLineItems [Line Items] |
Sensitivity level | 1.00%
Effect on current service cost and on interest on actuarial obligations | R$ | R$ 5,291
Effect on present value of obligations | shares | 50,127
Possible Increase In Actuarial Assumption [Member] | Actuarial Assumption Of Mortality Table [Member] |
IfrsStatementLineItems [Line Items] |
Effect on current service cost and on interest on actuarial obligations | R$ | R$ 3,880
Effect on present value of obligations | shares | 36,763
Sensitivity level, year | +1 year
Possible Decrease In Actuarial Assumption [Member] | Actuarial assumption of discount rates [member] |
IfrsStatementLineItems [Line Items] |
Sensitivity level | (0.50%)
Effect on current service cost and on interest on actuarial obligations | R$ | R$ (608)
Effect on present value of obligations | shares | 22,545
Actuarial Assumption Of Medical Inflation [Member] | Actuarial assumption of discount rates [member] |
IfrsStatementLineItems [Line Items] |
Sensitivity level | (1.00%)
Effect on current service cost and on interest on actuarial obligations | R$ | R$ (4,599)
Effect on present value of obligations | shares | (43,572)
Actuarial Assumption Of Mortality Table [Member] | Actuarial assumption of mortality rates [member] |
IfrsStatementLineItems [Line Items] |
Effect on current service cost and on interest on actuarial obligations | R$ | R$ (3,669)
Effect on present value of obligations | shares | (34,763)
Sensitivity level, year | - 1 year

X
- References No definition available. + Details
Name: | sid_EffectOnCurrentServiceCostAndOnInterestOnActuarialObligations1
Namespace Prefix: | sid_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | sid_EffectOnPresentValueOfObligations1
Namespace Prefix: | sid_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | sid_IfrsStatementLineItems
Namespace Prefix: | sid_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | sid_SensitivityLevel
Namespace Prefix: | sid_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | sid_SensitivityLevelYear
Namespace Prefix: | sid_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_DefinedBenefitPlansAxis=sid_HealthcarePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sid_PossibleActuarialAssumptionAxis=sid_PossibleIncreaseInActuarialAssumptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfDiscountRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=sid_ActuarialAssumptionOfMedicalInflationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=sid_ActuarialAssumptionOfMortalityTableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sid_PossibleActuarialAssumptionAxis=sid_PossibleDecreaseInActuarialAssumptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sid_PossibleActuarialAssumptionAxis=sid_ActuarialAssumptionOfMedicalInflationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sid_PossibleActuarialAssumptionAxis=sid_ActuarialAssumptionOfMortalityTableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfMortalityRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |