Basis of Presentation and Summary of Significant Accounting Policies (Recently Adopted Accounting Pronouncements Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Programming and other inventory	$ 10,363		$ 8,652
Retained earnings	$ 10,375		$ 8,494
Adoption of New Accounting Standards [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings				$ 350
Accounting Standards Update 2019-02 [Member] | Noncurrent Asset [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Programming and other inventory		$ 1,170