CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (Unaudited) Statement - USD ($) shares in Millions, $ in Millions	Total		Common Stock [Member]	Common Stock Including Additional Paid in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]		AOCI Attributable to Parent [Member]		Parent [Member]		Noncontrolling Interest [Member]
Shares, Issued, beginning balance at Sep. 30, 2017			402.4
Equity Based Compensation And Other Shares			0.1
Shares, Issued, ending balance at Dec. 31, 2017			402.5
Beginning Balance at Sep. 30, 2017	$ 6,119			$ 10,119	$ (20,590)	$ 17,124		$ (618)		$ 6,035		$ 84
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	553			0	0	537		0		537		16
Other comprehensive income/(loss) (Viacom and noncontrolling interests)	42			0	0	0		42		42		0
Noncontrolling interest	17			0	0	2		0		2		19
Dividends, Common Stock, Cash	(81)			0	0	(81)		0		(81)		0
Equity Based Compensation And Other Value	15			10	5	0		0		15		0
Ending Balance at Dec. 31, 2017	6,631			10,129	(20,585)	17,582		(576)		6,550		81
Shares, Issued, beginning balance at Sep. 30, 2018			403.1
Shares, Issued, beginning balance (ASC 606, ASU 2016-16 and ASU 2016-01, Shares [Member]) at Sep. 30, 2018			403.1
Stock Issued During Period, Shares, Issued for Services			0.0
Equity Based Compensation And Other Shares			0.0
Shares, Issued, ending balance at Dec. 31, 2018			403.1
Beginning Balance at Sep. 30, 2018	7,465			10,145	(20,562)	18,561		(737)		7,407		58
Beginning Balance (Accounting Standards Update 2014-09 [Member]) at Sep. 30, 2018	7,524			10,145	(20,562)	18,674		(791)		7,466		58
Cumulative Effect on Retained Earnings, Net of Tax	59	[1]		0	0	113	[1]	(54)	[1]	59	[1]	0	[1]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	334			0	0	321		0		321		13
Other comprehensive income/(loss) (Viacom and noncontrolling interests)	(51)			0	0	0		(48)		(48)		(3)
Noncontrolling interest	13			0	0	1		0		1		14
Dividends, Common Stock, Cash	(81)			0	0	(81)		0		(81)		0
Equity Based Compensation And Other Value	11			9	1	1		0		11		0
Ending Balance at Dec. 31, 2018	$ 7,724			$ 10,154	$ (20,561)	$ 18,916		$ (839)		$ 7,670		$ 54

[1] Represents the adoption of Accounting Standards Codification (“ASC”) 606 - Revenue from Contracts with Customers, Accounting Standards Update (“ASU”) 2016-16 - Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory and ASU 2016-01 - Financial Instruments - Overall: Recognition and Measurement of Financial Assets and Financial Liabilities. See Note 1 of the Consolidated Financial Statements for details.