v3.26.1
BASIS OF CONSOLIDATION AND INVESTMENTS (Details Narrative) - BRL (R$)
R$ / shares in Units, R$ in Thousands
12 Months Ended
Dec. 05, 2025
Oct. 21, 2022
Dec. 31, 2025
Dec. 31, 2024
Dec. 26, 2025
Nov. 04, 2025
May 08, 2025
Dec. 27, 2024
Nov. 05, 2024
Aug. 31, 2024
May 09, 2024
Dec. 31, 2023
Jun. 30, 2023
Dec. 31, 2022
IfrsStatementLineItems [Line Items]                            
Cancellation of shares description     On February 21, 2024, the company’s held its AGM, which resolved on the compulsory redemption and subsequent cancellation of 98,375 (ninety-eight thousand, three hundred and seventy-five) shares, of which 41,896 (forty-one thousand, eight hundred and ninety-six) and 56,479 (fifty-six thousand, four hundred and seventy-nine) were common and preferred shares issued by CEEE-G, respective, without making changes to the value of its share capital.                      
Net equity                         R$ 2,383,276  
Capital reserve     R$ 2,056,970 R$ 2,056,970                    
Number of stakeholders shares     5,485,338,835                      
Percentage of shareholdings     100.00%                      
Investment property     R$ 219,525 202,040               R$ 205,954   R$ 205,954
Investment property [member]                            
IfrsStatementLineItems [Line Items]                            
Investment property     3,818,752 R$ 2,431,581                    
C S N Cimentos Brasil S A [Member]                            
IfrsStatementLineItems [Line Items]                            
Net equity     2,383,276                      
Capital reserve     R$ 82,786                      
Interest in subsidiary     99.99% 99.99%                    
M R S Logistica S. A. [Member]                            
IfrsStatementLineItems [Line Items]                            
Transaction value     R$ 3,350,000                      
Investment amount     998,922                      
Gain operating revenues     2,351,078                      
C S N Mineracao [Member]                            
IfrsStatementLineItems [Line Items]                            
Profit reserve amount                   R$ 160,000 R$ 1,025,040      
Profit reserve per share                   R$ 0.02943266927 R$ 0.186869166032      
Dividends reserve amount     R$ 768,596   R$ 259,712 R$ 424,206 R$ 1,090,000     R$ 2,375,000        
Dividends per share                   R$ 0.43689118448        
Payment of interest on equity         R$ 163,998 R$ 479,000 R$ 178,201 R$ 211,610   R$ 465,000        
Payment of interest on equity per share               R$ 0.03895595758   R$ 0.08553869507        
Sale of common shares                 589,304,801          
Sale of common stock price per share                 R$ 7.50          
Sale of common shares value                 R$ 4,419,786          
C S N Mineracao S A [Member]                            
IfrsStatementLineItems [Line Items]                            
Stake percentage     69.01% 69.01%                    
Companhia Estadual De Geracaode Energia Eletrica C E E E G [Member]                            
IfrsStatementLineItems [Line Items]                            
Stake percentage   66.23%                        
C S N Cimentos Brasil S A [Member]                            
IfrsStatementLineItems [Line Items]                            
Stake percentage       99.99%                    
Global Dot Com S. A. [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary 80.00%                          
Additional interest R$ 49,900                          
C S N Inova Ventures [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     2.51%                      
C S N Inova Solucoes S. A. [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     77.49%                      
Companhia Sidurgica Nacional [Member]                            
IfrsStatementLineItems [Line Items]                            
Number of stakeholders shares     3,785,474,692                      
Percentage of shareholdings     69.01%                      
Itochu Corporation [Member]                            
IfrsStatementLineItems [Line Items]                            
Number of stakeholders shares     589,304,801                      
Percentage of shareholdings     10.74%                      
Japao Brasil Minerio De Ferro Participacoes Ltda [Member]                            
IfrsStatementLineItems [Line Items]                            
Number of stakeholders shares     507,762,966                      
Percentage of shareholdings     9.26%                      
Consorcio Da Usina Hidreletrica De Igarapava [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     17.92%                      
Consorcio Da Usina Hidreletrica De Itauba [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     99.99%                      
Consorcio Da Usina Hidreletrica De Itauba [Member] | Direct Interest [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     39.03%                      
Consorcio Da Usina Hidreletrica De Itauba [Member] | Indirect Interest [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     60.96%                      
Consorcio Da Usina Hidreletrica De Passo Real [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     96.55%                      
Consorcio Da Usina Hidreletrica De Passo Real [Member] | Direct Interest [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     56.40%                      
Consorcio Da Usina Hidreletrica De Passo Real [Member] | Indirect Interest [Member]                            
IfrsStatementLineItems [Line Items]                            
Interest in subsidiary     40.15%