Investments (Schedule of Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity investments without readily determinable fair values:	$ 571	$ 514
Total Investments	1,153	1,133
Equity method investments
Schedule of Equity Method Investments [Line Items]
Equity method investments	536	568
Equity method investments | nC+
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 176	182
Equity method investment, ownership percentage	32.00%
Equity method investments | Discovery Solar Ventures, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 85	92
Equity method investments | All3Media
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 45	75
Equity method investment, ownership percentage	50.00%
Equity method investments | Other
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 230	219
Other noncurrent assets | Group Nine Media
Schedule of Equity Method Investments [Line Items]
Equity investments without readily determinable fair values:	276	256
Note receivable	$ 20
Other noncurrent assets | Group Nine Media | Group Nine Media
Schedule of Equity Method Investments [Line Items]
Ownership percentage by noncontrolling owners	25.00%
Other noncurrent assets | Formula E
Schedule of Equity Method Investments [Line Items]
Equity investments without readily determinable fair values:	$ 65	65
Other noncurrent assets | Formula E | Formula E
Schedule of Equity Method Investments [Line Items]
Ownership percentage by noncontrolling owners	25.00%
Other noncurrent assets | Other
Schedule of Equity Method Investments [Line Items]
Equity investments without readily determinable fair values:	$ 230	193
Other noncurrent assets | Common Stock
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 46	$ 51