Reportable Segments (Operating Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Stock-based compensation	$ (57)	$ (50)	$ (145)	$ (106)
Depreciation and amortization	(124)	(109)	(237)	(215)
Restructuring and other corporate matters	(158)	(7)	(391)	(185)
Gain on sale of assets	0	0	0	549
Operating income	1,286	1,446	2,203	3,250
Interest expense	(263)	(237)	(504)	(477)
Interest income	11	15	25	34
Loss on extinguishment of debt	(103)	0	(103)	0
Other items, net	6	15	(27)	25
Earnings from continuing operations before income taxes and equity in loss of investee companies	937	1,239	1,594	2,832
(Provision) benefit for income taxes	(202)	(241)	(339)	135
Equity in loss of investee companies, net of tax	(12)	(21)	(21)	(39)
Net earnings from continuing operations	723	977	1,234	2,928
Net earnings from discontinued operations, net of tax	3	6	11	19
Net earnings (ViacomCBS and noncontrolling interests)	726	983	1,245	2,947
Net earnings attributable to noncontrolling interests	(245)	(6)	(248)	(11)
Net earnings attributable to ViacomCBS	481	977	997	2,936
Operating Segments [Member] | TV Entertainment [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	392	613	965	1,355
Operating Segments [Member] | Cable Networks [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	1,285	989	2,079	1,882
Operating Segments [Member] | Filmed Entertainment [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	116	95	143	133
Operating Segments [Member] | Publishing [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	38	35	57	54
Corporate [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	(97)	(120)	(193)	(222)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Stock-based compensation	(45)	(50)	(99)	(101)
Depreciation and amortization	(124)	(109)	(237)	(215)
Restructuring and other corporate matters	(158)	(7)	(391)	(185)
Programming charges	$ (121)	$ 0	$ (121)	$ 0