Revenues (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 6,874	$ 5,837	$ 6,075	$ 6,499	$ 6,656	$ 6,481	$ 6,925	$ 6,936	$ 25,285	$ 26,998	$ 26,425
Advertising [Member]
Disaggregation of Revenue [Line Items]
Revenues									9,751	11,074	10,841
Affiliate [Member]
Disaggregation of Revenue [Line Items]
Revenues									9,166	8,602	8,376
Content Licensing [Member]
Disaggregation of Revenue [Line Items]
Revenues									5,963	6,483	6,163
Theatrical [Member]
Disaggregation of Revenue [Line Items]
Revenues									180	547	744
Other [Member]
Disaggregation of Revenue [Line Items]
Revenues									$ 225	$ 292	$ 301