Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Total ViacomCBS Stockholders’ Equity [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interest [Member]
Balance, beginning of year (shares) at Dec. 31, 2019				615
Balance, beginning of year at Dec. 31, 2019	$ 13,289	$ 13,207		$ 1	$ 29,590	$ (22,908)	$ 8,494	$ (1,970)	$ 82
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation activity (shares)				1
Stock-based compensation activity	43	43			43
Common stock dividends	(150)	(150)					(150)
Class B Common Stock purchased (shares)				(1)
Class B Common Stock purchased	(50)	(50)				(50)
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
Balance, end of year at Mar. 31, 2020	13,521	13,449		$ 1	29,633	(22,958)	8,827	(2,054)	72
Balance, beginning of year (shares) at Dec. 31, 2020			0	617
Balance, beginning of year at Dec. 31, 2020	16,056	15,371	$ 0	$ 1	29,785	(22,958)	10,375	(1,832)	685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation activity (shares)				9
Stock-based compensation activity	426	426			426
Stock issuance (shares)			10	20
Stock issuances	2,655	2,655			2,655
Preferred stock dividends	(1)	(1)					(1)
Common stock dividends	(152)	(152)					(152)
Noncontrolling interests	(13)	11					11		(24)
Net earnings	923	911					911		12
Other comprehensive income (loss)	(51)	(50)						(50)	(1)
Balance, end of year (shares) at Mar. 31, 2021			10	646
Balance, end of year at Mar. 31, 2021	$ 19,843	$ 19,171	$ 0	$ 1	$ 32,866	$ (22,958)	$ 11,144	$ (1,882)	$ 672