Employee Benefits and Private Pension Plan - Significant actuarial assumptions adopted (Detail)	Dec. 31, 2018	Dec. 31, 2017
Employee benefits and private pension plan details 3 [abstract]
Discount rate for the actuarial obligation at present value	9.00%	9.51%
Average projected salary growth rate	7.85%	8.38%
Inflation rate (long term)	4.00%	4.50%
Growth rate of medical services	8.16%	8.68%

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant