Financial Instruments - Summary of Credit Receivable (Details) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017
Disclosure Of Financial Instruments [Abstract]
Trade receivables	$ 2,016	$ 1,900
Unbilled revenues	$ 654	$ 562

The amount of current accrued income. [Refer: Accrued income]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_CurrentAccruedIncome
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant