Acquisitions, Disposals and Other Transactions - Additional Information (Detail) $ / shares in Units, £ in Millions, AUD in Millions, $ in Millions				1 Months Ended					3 Months Ended			9 Months Ended
		Sep. 30, 2015 USD ($)	Sep. 30, 2015 GBP (£)	Feb. 29, 2016 USD ($) Tranche	Feb. 29, 2016 AUD Tranche	Jul. 31, 2015 USD ($)	Nov. 30, 2014 USD ($) $ / shares	Aug. 31, 2014 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Jan. 31, 2016	Sep. 30, 2015 GBP (£)
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition recognized gain resulting from remeasurement of previously held equity interest	[1]								$ 29		$ 0	$ 29	$ 0
REA Group [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Interest acquired							20.00%
Unruly Holdings Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity		$ 90	£ 60
Future cash consideration related to contingent payments		86								$ 86					£ 56
Future consideration related to contingent payments		40								40
Business acquisition purchase price allocation, goodwill amount		67
Unruly Holdings Limited [Member] | Acquired Technology [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, amortizable intangible assets		$ 42								42
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		$ 25								25
Finite lived intangible assets, weighted average useful life		6 years	6 years
Harlequin Enterprises Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity								$ 414
Business acquisition purchase price allocation, amortizable intangible assets								$ 60
Finite lived intangible assets, weighted average useful life								5 years
Business acquisition purchase price allocation, goodwill amount								$ 185
Business acquisition purchase price allocation, net intangible assets								165
Business acquisition purchase price allocation, cash								19
Business acquisition purchase price allocation, net tangible assets								115
Business acquisition purchase price allocation, non-amortizable intangible assets								105
Business acquisition purchase price allocation, deferred tax liability								$ 35
Move Inc [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity							$ 892
Business acquisition purchase price allocation, net intangible assets							216
Business acquisition purchase price allocation, cash							$ 108
Shares purchase price | $ / shares							$ 21.00
Business acquisition, cost of acquired entity, cash paid							$ 864
Fair value of assumed outstanding equity-based compensation awards							67
Assumed equity-based compensation awards - pre-combination services							28
Consideration transferred for future services							$ 39
Business combination, weighted average remaining service period							2 years 6 months
Business acquisition, cash paid for outstanding indebtedness							$ 129
Move Inc [Member] | U.S. Federal [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Net operating loss carryforwards							947
Net operating loss carryforwards, tax-effected							332
Valuation allowances and unrecognized tax benefits							484
Valuation allowances and unrecognized tax benefits, tax-effected							170
Expected net operating loss carryforwards to be utilized							463
Net deferred tax asset							162
Increase in expected net operating loss carryforwards										167
Increase in expected net operating loss carryforwards tax-effected										$ 58
Expected net operating loss carryforwards									630			630
Expected net operating loss carryforwards tax-effected									220			$ 220
Move Inc [Member] | Trademarks [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, non-amortizable intangible assets							116
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 intangible assets							$ 100
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 intangible assets							$ 39
Finite lived intangible assets, weighted average useful life							4 years
DIAKRIT International Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity				$ 40
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
Checkout 51 Mobile Apps ULC [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity						$ 13
Future cash consideration related to contingent payments						$ 28
iProperty Group Limited [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition purchase price allocation, goodwill amount				$ 505
Non-controlling ownership percentage				13.10%
Business acquisition recognized liability				$ 80
Minority interest ownership redeemable year												2018
Business acquisition purchase price allocation, net intangible assets				67
iProperty Group Limited [Member] | REA Group [Member]
Schedule Of Business Acquisitions And Divestitures [Line Items]
Business acquisition, cost of acquired entity				$ 340	AUD 482
Business acquisition, ownership percentage				86.90%										22.70%
Company ownership percentage				61.60%	61.60%
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			$ 29

[1] 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.