Acquisitions, Disposals and Other Transactions - Additional Information (Detail) £ / shares in Units, $ / shares in Units, € in Millions, £ in Millions, AUD in Millions				1 Months Ended										3 Months Ended		12 Months Ended
		Sep. 30, 2015 USD ($)	Sep. 30, 2015 GBP (£)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 GBP (£) £ / shares	May 31, 2016 USD ($)	Feb. 29, 2016 USD ($) Tranche	Feb. 29, 2016 AUD Tranche	Jul. 31, 2015 USD ($)	Nov. 30, 2014 USD ($) $ / shares	Aug. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2017 USD ($)		Jun. 30, 2016 USD ($)		Jun. 30, 2015 USD ($)		Jan. 31, 2016	Sep. 30, 2015 GBP (£)
Schedule Of Business Acquisitions And Divestitures [Line Items]
Restricted cash																$ 0		$ 315,000,000
Business acquisition purchase price allocation, goodwill amount																159,000,000		656,000,000
Deferred tax assets gross																1,911,000,000		1,931,000,000
Valuation allowances																1,187,000,000		1,014,000,000
Net deferred tax asset																464,000,000		431,000,000
REA Group [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Company ownership percentage				61.60%	61.60%
Cash consideration of sale of business				$ 140,000,000	€ 133
Gain on sale of business														$ 120,000,000		107,000,000	[1]	0	[1]	$ 0	[1]
REA Group [Member] | Move Inc [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Interest acquired												20.00%
Checkout 51 Mobile Apps ULC [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid											$ 13,000,000
Deferred cash consideration related to contingent payments																		10,000,000
Flatmates [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid								$ 19,000,000
Future cash consideration related to contingent payments								$ 15,000,000
Harlequin Enterprises Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, intangible assets													$ 105,000,000
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets													$ 60,000,000
Finite lived intangible assets, weighted average useful life													5 years
Business acquisition purchase price allocation, goodwill amount													$ 185,000,000
Business acquisition, cost of acquired entity													414,000,000
Business acquisition purchase price allocation, cash													19,000,000
Business acquisition purchase price allocation, net tangible assets													115,000,000
Business acquisition purchase price allocation, net intangible assets													165,000,000
Business acquisition purchase price allocation, deferred tax liability													$ 35,000,000
Move Inc [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid												$ 864,000,000
Assumed debt												129,000,000
Business acquisition, cost of acquired entity												892,000,000
Business acquisition purchase price allocation, cash												108,000,000
Business acquisition purchase price allocation, net intangible assets												$ 216,000,000
Shares purchase price | $ / shares												$ 21.00
Fair value of assumed outstanding equity-based compensation awards												$ 67,000,000
Assumed equity-based compensation awards - pre-combination services												28,000,000
Consideration transferred for future services												$ 39,000,000
Business combination, weighted average remaining service period												2 years 6 months
Business acquisition, cash paid for outstanding indebtedness												$ 129,000,000
Move Inc [Member] | U.S. Federal [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Net operating loss carryforwards												947,000,000
Deferred tax assets gross												332,000,000
Valuation allowances and unrecognized tax benefits												484,000,000
Valuation allowances												170,000,000
Expected net operating loss carryforwards to be utilized												463,000,000
Net deferred tax asset												162,000,000
Increase in expected net operating loss carryforwards															$ 167,000,000
Increase in expected net operating loss carryforwards tax-effected															58,000,000
Reduction in net operating loss carryforwards																298,000,000
Expected net operating loss carryforwards																		573,000,000
Expected net operating loss carryforwards tax-effected																		201,000,000
Move Inc [Member] | Trademarks [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, intangible assets												116,000,000
Move Inc [Member] | Customer Relationships Other Tradenames and Listing Service Agreements [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets												$ 100,000,000
Finite lived intangible assets, weighted average useful life												15 years
Move Inc [Member] | Technology-Based Intangible Assets [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets												$ 39,000,000
Finite lived intangible assets, weighted average useful life												4 years
Wireless Group plc [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid						$ 285,000,000	£ 220
Business acquisition, cost of acquired entity per share | £ / shares							£ 3.15
Assumed debt						23,000,000
Restricted cash																$ 0		315,000,000
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets						220,000,000
Wireless Group plc [Member] | Broadcast Licenses [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, intangible assets						185,000,000
Wireless Group plc [Member] | Trademarks [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, intangible assets						27,000,000
Wireless Group plc [Member] | Customer Relationships [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets						$ 8,000,000
Finite lived intangible assets, weighted average useful life						6 years	6 years
Australian Regional Media [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid				$ 30,000,000
Unruly Holdings Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid		$ 90,000,000	£ 60
Future cash consideration related to contingent payments		86,000,000													86,000,000								£ 56
Future consideration related to contingent payments		40,000,000													40,000,000
Business acquisition purchase price allocation, goodwill amount		68,000,000
Unruly Holdings Limited [Member] | Acquired Technology [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets		$ 43,000,000													43,000,000
Finite lived intangible assets, weighted average useful life		7 years	7 years
Unruly Holdings Limited [Member] | Customer Relationships and Trade Names [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets		$ 21,000,000													$ 21,000,000
Finite lived intangible assets, weighted average useful life		6 years	6 years
DIAKRIT International Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid									$ 40,000,000
Business acquisition, acquired interest percentage									92.00%
Non-controlling ownership percentage									8.00%
Number of tranches | Tranche									2	2
Option to sell minority interest, period									6 years	6 years
iProperty Group Limited [Member] | REA Group [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid									$ 340,000,000	AUD 482
Business acquisition purchase price allocation, amortizable and indefinite lived intangible assets									$ 72,000,000
Non-controlling ownership percentage									13.10%
Business combination, ownership percentage prior to acquisition date																						22.70%
Business acquisition, ownership percentage									86.90%
Amount expected to be paid for remaining interest									$ 76,000,000
Minority interest ownership redeemable year																2018
Business acquisition recognized gain resulting from remeasurement of previously held equity interest	[2]															$ 0		29,000,000		$ 0
Business acquisition, cost of acquired entity									$ 416,000,000
iProperty Group Limited [Member] | REA Group [Member] | Other, Net [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition recognized gain resulting from remeasurement of previously held equity interest																		$ 29,000,000

[1] The Company recognized a pre-tax gain of $107 million for the fiscal year ended June 30, 2017 related to REA Group's sale of its European business. See Note 3-Acquisitions, Disposals and Other Transactions.

[2] See Note 3-Acquisitions, Disposals and Other Transactions.