Reportable Segments (Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 51,425	$ 49,519
Operating Segments [Member] | TV Entertainment [Member]
Segment Reporting Information [Line Items]
Assets	19,018	19,689
Assets held for sale total	271
Operating Segments [Member] | Cable Networks [Member]
Segment Reporting Information [Line Items]
Assets	22,434	22,109
Assets held for sale total	23	23
Operating Segments [Member] | Filmed Entertainment [Member]
Segment Reporting Information [Line Items]
Assets	6,354	5,477
Assets held for sale total	5
Operating Segments [Member] | Publishing [Member]
Segment Reporting Information [Line Items]
Assets	1,320	1,262
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Assets	$ 2,299	$ 982