Employee Benefit Obligations - Summary of Assumptions Used in Actuarial Calculation of Defined Benefits (Detail)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Sensitivity Analysis For Actuarial Assumptions [Abstract]
Discount rates used	3.40%	4.70%
Expected rate of salary increases	3.80%	3.80%
Turnover rate	5.24%	4.40%
Mortality tables	CB-H-2014 / RV-M-2014	CB-H-2014 / RV-M-2014

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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2019-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=19&code=ifrs-tx-2019-en-r&anchor=para_144&doctype=Standard
-URIDate 2019-03-27

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