GOODWILL (Details) - Goodwill - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Reconciliation of changes in intangible assets and goodwill [abstract]
Balance at beginning of the year	$ 667	$ 691
Foreign currency translation and other	(139)	(24)
Balance at end of the year	$ 528	$ 667

The increase (decrease) in intangible assets and goodwill resulting from the net exchange differences arising when the financial statements are translated from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Intangible assets and goodwill]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 38
-IssueDate 2020-01-01
-Paragraph 118
-Subparagraph e
-Clause vii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_e_vii&doctype=Standard
-URIDate 2020-01-01

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