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Post-Employment Obligations - Schedule of Changes in Present Value of Defined Benefit Obligation (Details) - BRL (R$) R$ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
IfrsStatementLineItems [Line Items] |  |  |  |  |  |
Defined-benefit obligation, beginning balance | R$ 13,105 | R$ 15,276 | R$ 14,778 |  | R$ 15,561 |
Cost of current service |  | 7 | 11 |  | 18 |
Past service cost |  |  | (56) |  | (4) |
Interest on actuarial obligation |  | 1,322 | 1,653 |  | 1,592 |
Actuarial losses (gains): |  |  |  |  |  |
Due to changes in demographic assumptions |  | (1) | 27 |  | (8) |
Due to changes in financial assumptions |  | (2,448) | 990 |  | (1,168) |
Due to adjustments based on experience |  | 269 | (812) |  | 83 |
Due to changes and adjustments |  | (2,180) | 205 |  | (1,093) |
Benefits paid |  | (1,320) | (1,315) |  | (1,296) |
Net defined benefit liability (asset) |  | 13,105 | 15,276 |  | 14,778 |
Pension plans and retirement supplement plans [member] |  |  |  |  |  |
IfrsStatementLineItems [Line Items] |  |  |  |  |  |
Defined-benefit obligation, beginning balance | 10,501 | 12,216 | 11,404 |  | 12,026 |
Cost of current service | 1 | 1 |  |  | 2 |
Past service cost |  |  |  | [1] | (4) | [2]
Interest on actuarial obligation | 1,222 | 1,055 | 1,276 |  | 1,224 |
Actuarial losses (gains): |  |  |  |  |  |
Due to changes in demographic assumptions |  |  |  |  | (7) |
Due to changes in financial assumptions |  | (1,883) | 754 |  | (857) |
Due to adjustments based on experience |  | 232 | (125) |  | 106 |
Due to changes and adjustments |  | (1,651) | 629 |  | (758) |
Benefits paid |  | (1,120) | (1,093) |  | (1,086) |
Net defined benefit liability (asset) |  | 10,501 | 12,216 |  | 11,404 |
Health plan [member] |  |  |  |  |  |
IfrsStatementLineItems [Line Items] |  |  |  |  |  |
Defined-benefit obligation, beginning balance | 2,559 | 3,007 | 3,314 |  | 3,469 |
Cost of current service | 4 | 6 | 11 |  | 16 |
Past service cost |  |  | (55) |  |  |
Interest on actuarial obligation | 301 | 262 | 370 |  | 361 |
Actuarial losses (gains): |  |  |  |  |  |
Due to changes in demographic assumptions |  | (1) | 26 |  | (1) |
Due to changes in financial assumptions |  | 556 | 232 |  | (305) |
Due to adjustments based on experience |  | 38 | (673) |  | (20) |
Due to changes and adjustments |  | (519) | (415) |  | (326) |
Benefits paid |  | (197) | (218) |  | (206) |
Net defined benefit liability (asset) |  | 2,559 | 3,007 |  | 3,314 |
Dental plan [member] |  |  |  |  |  |
IfrsStatementLineItems [Line Items] |  |  |  |  |  |
Defined-benefit obligation, beginning balance | 45 | 53 | 60 |  | 66 |
Cost of current service |  |  |  |  |  |
Past service cost |  |  | (1) |  |  |
Interest on actuarial obligation | R$ 5 | 5 | 7 |  | 7 |
Actuarial losses (gains): |  |  |  |  |  |
Due to changes in demographic assumptions |  |  | 1 |  |  |
Due to changes in financial assumptions |  | (9) | 4 |  | (6) |
Due to adjustments based on experience |  | (1) | (14) |  | (3) |
Due to changes and adjustments |  | (10) | (9) |  | (9) |
Benefits paid |  | (3) | (4) |  | (4) |
Net defined benefit liability (asset) |  | R$ 45 | R$ 53 |  | R$ 60 |
[1] | Relating to the changes in the conditions of Plan B for requesting the Enhancement of Retirement for Length of Contribution, Special or Age - MAT (Melhoria de Aposentadoria por Tempo de Contribuição, Especial ou or Idade).
[2] | Due to the alterations made in the Collective Work Agreement for 2021-23, for offer and payment of life insurance for the employees and former employees, the Company understood that the post-retirement benefit in question had been entirely canceled, and as a result wrote down the balance of the obligation, remeasured using the revised actuarial assumptions.

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- Definition Actuarial gains (losses) arising from adjustments based on experience net defined benefit liability (asset). + References No definition available. + Details
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- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2024-01-01 -Paragraph 141 -Subparagraph c -Clause ii -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_141_c_ii&doctype=Standard -URIDate 2024-03-27 + Details
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- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2024-01-01 -Paragraph 141 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_141_a&doctype=Standard -URIDate 2024-03-27 + Details
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