Employee Benefits - Summary of Sensitivity of Significant Assumptions Used for Valuation of Defined Benefit Obligation (Details) - Benefit Obligations $ in Millions	Mar. 31, 2018 USD ($)
Discount Rate
Disclosure Of Sensitivity Analysis For Actuarial Assumptions [Line Items]
Impact from percentage point increase / decrease	$ 9
Increase in Compensation Levels \| Weighted Average
Disclosure Of Sensitivity Analysis For Actuarial Assumptions [Line Items]
Impact from percentage point increase / decrease	$ 8

The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 145
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_145_a&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant