Reportable Segments (Operating Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Stock-based compensation	$ (88)	$ (56)
Depreciation and amortization	(113)	(106)
Restructuring and other corporate matters	(233)	(178)
Gain on sale of assets	0	549
Operating income	917	1,804
Interest expense	(241)	(240)
Interest income	14	19
Gain on marketable securities	0	38
Other items, net	(33)	(28)
Earnings from continuing operations before income taxes and equity in loss of investee companies	657	1,593
(Provision) benefit for income taxes	(137)	376
Equity in loss of investee companies, net of tax	(9)	(18)
Net earnings from continuing operations	511	1,951
Net earnings from discontinued operations, net of tax	8	13
Net earnings (ViacomCBS and noncontrolling interests)	519	1,964
Net earnings attributable to noncontrolling interests	(3)	(5)
Net earnings attributable to ViacomCBS	516	1,959
Operating Segments [Member] | TV Entertainment [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	573	742
Operating Segments [Member] | Cable Networks [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	794	893
Operating Segments [Member] | Filmed Entertainment [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	27	38
Operating Segments [Member] | Publishing [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	19	19
Corporate [Member]
Segment Reporting Information [Line Items]
Adjusted OIBDA	(96)	(102)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Stock-based compensation	(54)	(51)
Depreciation and amortization	(113)	(106)
Restructuring and other corporate matters	$ (233)	$ (178)