Taxes, Income Tax and Social Contribution - Summary of Income Tax and Social Contribution Tax (Detail) - BRL (R$) R$ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Disclosure of taxes, income tax and social contribution tax [abstract]
Income tax	R$ 88	R$ 19
Social contribution tax	27	8
Total income and social contribution tax	R$ 115	R$ 27

The amount of current tax expense (income) and adjustments for the current tax of prior periods. [Refer: Current tax expense (income); Adjustments for current tax of prior periods]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 12
-IssueDate 2017-01-01
-Paragraph 80
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2017-03-01&anchor=para_80&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration