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26. POST-EMPLOYMENT OBLIGATIONS (Details) - BRL (R$) R$ in Millions | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | R$ 6,709 | R$ 4,989 | R$ 4,186 | R$ 4,242
Pension Plans and Retirement Supplement Plans [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Fair value of plan assets | (10,366) | (9,063) | (8,546) | (8,128)
Pension And Retirement Supplement Plans [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 2,972 | 2,170 | 2,068 | 1,679
Dental Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 61 | 48 | 38 | 38
Health Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 3,102 | 2,344 | 1,809 | 1,711
Life Insurance Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 574 | 427 | R$ 271 | R$ 814
Actuarial Assumption of Expected Rates of Pension Increases [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Present value of obligations | 17,022 | 13,892 |  |
Fair value of plan assets | (10,366) | (9,062) |  |
Net liabilities in the statement of financial position | 6,709 | 4,989 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Initial Net Liabilities [member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 6,656 | 4,830 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Effect of Asset Ceiling [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 53 | 159 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Pension Plans and Retirement Supplement Plans [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Present value of obligations | 13,285 | 11,073 |  |
Fair value of plan assets | (10,366) | (9,062) |  |
Net liabilities in the statement of financial position | 2,972 | 2,170 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Pension Plans and Retirement Supplement Plans [Member] | Initial Net Liabilities [member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 2,919 | 2,011 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Pension Plans and Retirement Supplement Plans [Member] | Effect of Asset Ceiling [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 53 | 159 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Dental Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Present value of obligations | 61 | 48 |  |
Net liabilities in the statement of financial position | 61 | 48 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Dental Plan [Member] | Initial Net Liabilities [member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 61 | 48 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Life Insurance [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Present value of obligations | 574 | 427 |  |
Net liabilities in the statement of financial position | 574 | 427 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Life Insurance [Member] | Initial Net Liabilities [member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | 574 | 427 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Health Plan [Member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Present value of obligations | 3,102 | 2,344 |  |
Net liabilities in the statement of financial position | 3,102 | 2,344 |  |
Actuarial Assumption of Expected Rates of Pension Increases [Member] | Health Plan [Member] | Initial Net Liabilities [member] |  |  |  |
Disclosure of defined benefit plans [line items] |  |  |  |
Net liabilities in the statement of financial position | R$ 3,102 | R$ 2,344 |  |

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- Definition The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 57 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_57_a&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 57 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_57_a&doctype=Standard -URIDate 2019-03-27 + Details
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- Definition The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 19 -IssueDate 2019-01-01 -Paragraph 57 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_57_a&doctype=Standard -URIDate 2019-03-27 + Details
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