Acquisitions, Disposals and Other Transactions - Additional Information (Detail) £ / shares in Units, € in Millions, £ in Millions, AUD in Millions				1 Months Ended								3 Months Ended				9 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 ($) Tranche	Feb. 29, 2016 AUD Tranche	Jul. 31, 2015 USD ($)	Mar. 31, 2017 USD ($)		Dec. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($)		Mar. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Jan. 31, 2016	Sep. 30, 2015 GBP (£)
Schedule Of Business Acquisitions And Divestitures [Line Items]
Restricted cash												$ 0				$ 0			$ 315,000,000
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												(13,000,000)	[1]	$ 120,000,000		107,000,000	[1]
REA Group [Member] | Other, Net [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Gain on sale of business												13,000,000
Wireless Group plc [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid						$ 285,000,000	£ 220									285,000,000
Business acquisition, cost of acquired entity per share | £ / shares							£ 3.15
Assumed debt						23,000,000						23,000,000				23,000,000
Restricted cash												0				0
Business acquisition purchase price allocation, amortizable intangible assets						$ 213,000,000
Wireless Group plc [Member] | Broadcast Licenses [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, non-amortizable intangible assets												178,000,000				178,000,000
Wireless Group plc [Member] | Trademarks [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, non-amortizable intangible assets												27,000,000				27,000,000
Wireless Group plc [Member] | Customer Relationships [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable intangible assets												$ 8,000,000				$ 8,000,000
Finite lived intangible assets, weighted average useful life																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
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
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																			£ 56
Future consideration related to contingent payments		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 intangible assets		$ 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 intangible assets		$ 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]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity, cash paid									$ 340,000,000
Business acquisition purchase price allocation, amortizable intangible assets									72,000,000
Business acquisition recognized gain resulting from remeasurement of previously held equity interest	[2]														$ 29,000,000			$ 29,000,000
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
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
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				$ 29,000,000
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

[1] In December 2016, REA Group sold its European business for approximately $140 million (approximately € 133 million) in cash, which resulted in a pre-tax gain of $120 million in the second quarter of fiscal 2017. The gain was partially offset in the third quarter of fiscal 2017 by $13 million related to the impact of foreign currency fluctuations on the receipt of the sales proceeds, which were received in February 2017, and certain other currency translation impacts. The sale allows REA Group to focus on its core businesses in Australia and Asia.

[2] The Company recorded a $29 million gain resulting from the revaluation of REA Group's previously held equity interest in iProperty. (See Note 2-Acquisitions, Disposals and Other Transactions).