Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Accounting Policies [Line Items]
Number of significant gross accounts receivable Recorded Music customers | Customer	0
Advertising expense	$ 91	$ 88	$ 83
ASU 2015-17
Accounting Policies [Line Items]
Decrease in current deferred tax assets	52
Increase in non-current deferred tax assets	2
Decrease in non-current deferred tax liabilities	$ 50
Furniture and Fixtures | Minimum
Accounting Policies [Line Items]
Property plant and equipment useful life	5 years
Furniture and Fixtures | Maximum
Accounting Policies [Line Items]
Property plant and equipment useful life	7 years
Computer Equipment | Maximum
Accounting Policies [Line Items]
Property plant and equipment useful life	5 years
Machinery and Equipment | Maximum
Accounting Policies [Line Items]
Property plant and equipment useful life	5 years
Building | Maximum
Accounting Policies [Line Items]
Property plant and equipment useful life	40 years