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Segment Information - Additional Information (Details)	12 Months Ended
	Sep. 30, 2020 Customer segment	Sep. 30, 2019 Customer	Sep. 30, 2018 Customer
Segment Reporting Information [Line Items]
Number of fundamental operations | segment	2
Recorded Music And Music Publishing Segments | Sales Revenue, Net | Credit Concentration Risk
Segment Reporting Information [Line Items]
Number of customers | Customer	2	2	2
Recorded Music And Music Publishing Segments | Sales Revenue, Net | Credit Concentration Risk | Spotify
Segment Reporting Information [Line Items]
Customer concentration percentage	17.00%	13.00%
Recorded Music And Music Publishing Segments | Sales Revenue, Net | Credit Concentration Risk | Apple
Segment Reporting Information [Line Items]
Customer concentration percentage	14.00%	14.00%	15.00%

X

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

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