The amount of current financial assets. [Refer: Financial assets]

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The amount of current financial liabilities. [Refer: Financial liabilities]

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The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose the entity’s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. [Refer: Financial instruments, class [member]; Financial liabilities]

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The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

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The amount of non-current financial assets. [Refer: Financial assets]

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The amount of non-current financial liabilities. [Refer: Financial liabilities]

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Current financial assets (liabilities), net.

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Disclosure Of Financial Assets and Financial Liabilities [line items]

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Noncurrent financial assets (liabilities), net.

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No definition available.

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Concession Financial and Sector Assets and Liabilities - Summary of Financial Assets and Financial Liabilities With the Tariff Adjustments (Detail) - BRL (R$) R$ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Financial Assets and Financial Liabilities [line items]
Assets	R$ 16,279	R$ 16,866
Current assets	1,071	848
Non-current assets	4,927	6,605
Liabilities	(18,120)	(19,556)
Current liabilities		415
Financial assets (liabilities), net	1,080	(46)	R$ (407)	R$ 1,350
CVA account for compensation of changes in portion A costs [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Assets	3,729	2,713
Current assets	2,689	1,761
Non-current assets	1,040	952
Liabilities	(2,649)	(2,759)
Current liabilities	(2,042)	(2,018)
Non-current liabilities	(607)	(741)
Total current, net	647	(257)
Total non-current,net	433	211
Financial assets (liabilities), net	1,080	(46)
CVA account for compensation of changes in portion A costs [member] \| Quota for the Energy Development Account [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	221	(244)
CVA account for compensation of changes in portion A costs [member] \| Tariff for Use of Transmission Facilities of Grid Participants [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	18	33
CVA account for compensation of changes in portion A costs [member] \| Tariff for Transport of Electricity Provided by Itaiputs [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	18	4
CVA account for compensation of changes in portion A costs [member] \| Program to Encourage Alternative Sources of Electricity Proinfa [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	8	(4)
CVA account for compensation of changes in portion A costs [member] \| System Service Charges and Reserve Energy Charge [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(533)	(627)
CVA account for compensation of changes in portion A costs [member] \| Energy purchased for resale [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	2,069	1,236
CVA account for compensation of changes in portion A costs [member] \| Over contracting of Supply [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(217)	(203)
CVA account for compensation of changes in portion A costs [member] \| Neutrality of Portion A [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	38	43
CVA account for compensation of changes in portion A costs [member] \| Other Financial Items [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(448)	(112)
CVA account for compensation of changes in portion A costs [member] \| Customer charges the Flag Tariff system [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(11)	(134)
CVA account for compensation of changes in portion A costs [member] \| Excess demand and reactive power [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(83)	(38)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Assets	1,184	382
Current assets	1,184	382
Liabilities	(1,140)	(797)
Current liabilities	(1,140)	(797)
Total current, net	44	(415)
Financial assets (liabilities), net	44	(415)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Quota for the Energy Development Account [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	1	(154)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Tariff for Use of Transmission Facilities of Grid Participants [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	24	9
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Tariff for Transport of Electricity Provided by Itaiputs [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	2	2
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Program to Encourage Alternative Sources of Electricity Proinfa [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	3	(5)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| System Service Charges and Reserve Energy Charge [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(246)	(40)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Energy purchased for resale [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	667	(91)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Over contracting of Supply [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(204)	8
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Neutrality of Portion A [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	53	(30)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Other Financial Items [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(236)	(112)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the last tariff adjustment [member] \| Excess demand and reactive power [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(21)	(2)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Assets	2,545	2,331
Current assets	1,505	1,379
Non-current assets	1,040	952
Liabilities	(1,509)	(1,962)
Current liabilities	(902)	(1,221)
Non-current liabilities	(607)	(741)
Total current, net	603	158
Total non-current,net	433	211
Financial assets (liabilities), net	1,036	369
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Quota for the Energy Development Account [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	220	(90)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Tariff for Use of Transmission Facilities of Grid Participants [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(6)	24
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Tariff for Transport of Electricity Provided by Itaiputs [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	16	2
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Program to Encourage Alternative Sources of Electricity Proinfa [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	5	1
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| System Service Charges and Reserve Energy Charge [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(287)	(587)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Energy purchased for resale [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	1,402	1,327
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Over contracting of Supply [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(13)	(211)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Neutrality of Portion A [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(15)	73
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Other Financial Items [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(212)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Customer charges the Flag Tariff system [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	(11)	(134)
CVA account for compensation of changes in portion A costs [member] \| Amounts ratified by Aneel in the next tariff adjustment [member] \| Excess demand and reactive power [member]
Disclosure Of Financial Assets and Financial Liabilities [line items]
Financial assets (liabilities), net	R$ (62)	R$ (36)