Cover - USD ($) $ in Billions	12 Months Ended
	Sep. 30, 2022	Nov. 16, 2022	Apr. 01, 2022
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2022
Current Fiscal Year End Date	--09-30
Document Transition Report	false
Entity File Number	001-32502
Entity Registrant Name	Warner Music Group Corp.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-4271875
Entity Address, Address Line One	1633 Broadway
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10019
City Area Code	(212)
Local Phone Number	275-2000
Title of 12(b) Security	Class A Common Stock, $0.001 par value per share
Trading Symbol	WMG
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 5.5
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCEPortions of the registrant's Proxy Statement for the 2022 Annual Meeting of Stockholders are incorporated herein by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant's fiscal year ended September 30, 2022.
Amendment Flag	false
Entity Central Index Key	0001319161
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Common Class A
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		137,203,473
Common Class B
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		377,650,449