Principal joint ventures - Reconciliation of financial information for joint ventures by carrying value (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Disclosure Of Joint Ventures [Line Items]
– deferred tax liabilities	$ 3,628	$ 3,121
Investment in equity accounted units [member]
Disclosure Of Joint Ventures [Line Items]
– deferred tax liabilities	$ 500	$ 579

The amounts of income taxes payable in future periods in respect of taxable temporary differences. [Refer: Temporary differences [member]]

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