Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Total ViacomCBS Stockholders’ Equity [Member]	Noncontrolling Interest [Member]
Balance, beginning of year (shares) at Dec. 31, 2018		613.0
Balance, beginning of year at Dec. 31, 2018	$ 10,503	$ 1	$ 49,907	$ (43,420)	$ 5,569	$ (1,608)	$ 10,449	$ 54
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation activity (shares)		2.0
Stock-based compensation activity and other	24		20	8	(4)		24
Dividends	(150)				(150)		(150)
Noncontrolling interests	(23)				(10)		(10)	(13)
Net earnings	1,964				1,959		1,959	5
Reclassification of income tax effect of the Tax Reform Act	(230)				230	(230)
Other comprehensive income (loss)	30					27	27	3
Balance, end of year (shares) at Mar. 31, 2019		615.0
Balance, end of year at Mar. 31, 2019	12,348	$ 1	49,927	(43,412)	7,594	(1,811)	12,299	49
Balance, beginning of year (shares) at Dec. 31, 2019		615.0
Balance, beginning of year at Dec. 31, 2019	13,289	$ 1	29,590	(22,908)	8,494	(1,970)	13,207	82
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation activity (shares)		1.0
Stock-based compensation activity and other	$ 43		43	0			43
Class B Common Stock purchased (shares)	(1.3)	(1.0)
Class B Common Stock purchased	$ (50)			(50)			(50)
Dividends	(150)				(150)		(150)
Noncontrolling interests	(43)				(33)		(33)	(10)
Net earnings	519				516		516	3
Other comprehensive income (loss)	(87)					(84)	(84)	(3)
Balance, end of year (shares) at Mar. 31, 2020		615.0
Balance, end of year at Mar. 31, 2020	$ 13,521	$ 1	$ 29,633	$ (22,958)	$ 8,827	$ (2,054)	$ 13,449	$ 72