XML 182 R186.htm IDEA: XBRL DOCUMENT v3.20.1

26 EMPLOYEE BENEFITS (Details 16)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
EmployeeBenefitsLineItems [Line Items]
General mortality table	Millennium Plan: 9.69% Plan 35%: 9.60% Supplementation: 9.59%	Millennium Plan: AT-2000 smoothed down by 10% segregated by gender. Plans 35%: AT-2000 Male aggravated by 15%. Supplementation: AT-2000 aggravated by 10% segregated by gender.
Inflation rate	3.61%	4.75%
Post-employment Healthcare Benefits [Member]
EmployeeBenefitsLineItems [Line Items]
General mortality table	AT 2000 segregated by gender	AT 2000 segregated by gender
Actuarial nominal discount rate	6.78%	9.62%
Inflation rate	3.61%	4.75%
Real increase in medical costs based on age (Aging Factor)	0,5% - 3,00% real a.a.	0.5% - 3.00%real a.a
Nominal increase medical costs growth rate	6.98%	8.15%
Average medical cost	131936.00%	105465.00%

X

- Definition

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2019-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2019-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflation
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Medical cost trend rate used as significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2019-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard
-URIDate 2019-03-27

+ Details

Name:	ifrs-full_ActuarialAssumptionOfMedicalCostTrendRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Represents the information about average medical cost (Claim cost).

+ References

No definition available.

+ Details

Name:	sid_AverageMedicalCostClaimCost
Namespace Prefix:	sid_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	sid_EmployeeBenefitsLineItems
Namespace Prefix:	sid_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the information about general mortality table.

+ References

No definition available.

+ Details

Name:	sid_GeneralMortalityTableDescription
Namespace Prefix:	sid_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Real increase in medical costs based on age (Aging Factor)

+ References

No definition available.

+ Details

Name:	sid_RealIncreaseInMedicalCostsBasedOnAgeAgingFactor
Namespace Prefix:	sid_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=sid_PostEmploymentHealthcareBenefitsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: