Adoption of hedge accounting requirements of IFRS 9, Financial Instruments (Narrative) (Detail) $ in Millions	3 Months Ended
Jun. 30, 2020 USD ($)
Disclosure Of Adoption Of Hedge Accounting Requirements Of IFRS 9 [Line Items]
Notional amount of hedging instruments and hedged items designated in fair value hedge program of foreign currency risk of issued debt hedged by cross currency basis swaps	$ 13,700
Comprehensive income attributable to shareholders
Disclosure Of Adoption Of Hedge Accounting Requirements Of IFRS 9 [Line Items]
Cost of hedging, net of tax	$ 9

The amount of other comprehensive income, net of tax, related to change in value of foreign currency basis spreads. [Refer: Other comprehensive income]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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