Acquisitions, Disposals and Other Transactions (Narrative) (Details) $ in Millions, $ in Millions	1 Months Ended					3 Months Ended	9 Months Ended		12 Months Ended
	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) TelevisionStation	Oct. 31, 2019 USD ($)	Oct. 31, 2019 AUD ($)	May 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired							$ 611	$ 0
Cash paid to acquire businesses							626	0
Consideration transferred preliminarily allocated to goodwill		$ 3,089				$ 3,089	3,089		$ 2,691
Sale of investments							349	$ 0
Roku
Business Acquisition [Line Items]
Sale of investments		$ 340
Change in fair value, loss						470	$ 210
The Stars Group
Business Acquisition [Line Items]
Payments to acquire investments					$ 236
Percentage of ownership of equity interest					4.99%
Transfer restrictions period					2021-05
Caffeine and Caffeine Studios
Business Acquisition [Line Items]
Payments to acquire investments									$ 100
FanDuel Group
Business Acquisition [Line Items]
Percentage of ownership interest that can be acquired in the future			18.50%
Option term to acquire an equity interest			10 years	10 years
Minimum
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to amortizable intangible assets, useful life							5 years
Maximum
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to amortizable intangible assets, useful life							20 years
Maximum | The Stars Group's U.S. business
Business Acquisition [Line Items]
Percentage of ownership interest that can be acquired in the future					50.00%
WJZY and WMYT Television Stations | Disposal
Business Acquisition [Line Items]
Number of television stations sold | TelevisionStation		2
Disposition, cash received		$ 45
KCPQ, KZJO and WITI Television Stations
Business Acquisition [Line Items]
Number of television stations acquired | TelevisionStation		3
Cash paid to acquire businesses		$ 350
Consideration transferred		350
Consideration transferred preliminarily allocated to intangible assets		210				210	$ 210
Consideration transferred preliminarily allocated to amortizable intangible assets		100				100	100
Consideration transferred preliminarily allocated to property, plant and equipment		$ 30				30	30
KCPQ, KZJO and WITI Television Stations | Retransmission Agreements
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to amortizable intangible assets, useful life		8 years
KCPQ, KZJO and WITI Television Stations | FCC licenses
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to intangible assets with indefinite lives		$ 110				$ 110	$ 110
Credible
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired			$ 260	$ 390
Consideration transferred			260
Consideration transferred preliminarily allocated to amortizable intangible assets			$ 70
Business acquisition, percentage of equity acquired			67.00%
Provisional valuation, percentage of acquired business			100.00%	100.00%
Consideration transferred preliminarily allocated to goodwill			$ 285
Consideration transferred preliminarily allocated to redeemable noncontrolling interests			(110)
Maximum capital to be contributed			$ 75
Period over which capital will be contributed			2 years	2 years
Credible | Credible
Business Acquisition [Line Items]
Remaining percentage of equity not acquired by parent			33.00%
Credible | Minimum
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to amortizable intangible assets, useful life			5 years	5 years
Credible | Maximum
Business Acquisition [Line Items]
Consideration transferred preliminarily allocated to amortizable intangible assets, useful life			10 years	10 years
Subsequent Event | Tubi Inc
Business Acquisition [Line Items]
Payments to acquire businesses, net of cash acquired	$ 445
Additional consideration to be transferred	$ 45