XML 65 R49.htm IDEA: XBRL DOCUMENT
v3.25.3

Description of Business (Details) | 12 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2025 segment $ / shares | Sep. 30, 2024 $ / shares | Jun. 05, 2020 $ / shares
Subsidiary, Sale of Stock [Line Items] |  |  |
Number of fundamental operations | segment | 2 |  |
Access Industries |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Sale of stock, percentage of ownership after transaction (as a percent) | 98.00% |  |
Sale of stock, percentage of economic interest (as a percent) | 72.00% |  |
Class A Common Stock |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Common stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
Class A Common Stock | IPO |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Common stock, par value (in dollars per share) |  |  | $ 0.001
Class B Common Stock |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Common stock, par value (in dollars per share) | 0.001 | $ 0.001 |
Class B Common Stock | Access Industries |  |  |
Subsidiary, Sale of Stock [Line Items] |  |  |
Common stock, par value (in dollars per share) | $ 0.001 |  |

X
- Definition Face amount or stated value per share of common stock. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- 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 Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 49 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482785/280-10-55-49 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-18 + Details
Name: | us-gaap_NumberOfOperatingSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of subsidiary's or equity investee's stock owned by parent company after stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPercentageOfOwnershipAfterTransaction
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SubsidiarySaleOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sale Of Stock, Percentage Of Economic Interest + References No definition available. + Details
Name: | wmg_SaleOfStockPercentageOfEconomicInterest
Namespace Prefix: | wmg_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=wmg_AccessIndustriesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |