Acquisitions, Disposals and Other Transactions - Schedule of Total Fair Value of iProperty at Acquisition Date (Detail) - 1 months ended Feb. 29, 2016 - iProperty Group Limited [Member] - REA Group [Member] AUD in Millions, $ in Millions	USD ($)	AUD
Business Acquisition [Line Items]
Cash paid for iProperty equity	$ 340	AUD 482
Deferred consideration	76
Total consideration	416
The fair value of the previously held equity investment subsequent to step acquisition remeasurement	120
Total fair value	$ 536