Cover - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 11, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-01520
Entity Registrant Name	Aerojet Rocketdyne Holdings, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	34-0244000
Entity Address, Address Line One	222 N. Pacific Coast Highway
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	El Segundo
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90245
City Area Code	(310)
Local Phone Number	252-8100
Title of 12(b) Security	Common stock, $0.10 par value
Trading Symbol	AJRD
Security Exchange Name	NYSE
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 Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 3.9
Entity Common Stock, Shares Outstanding		80,544,197
Documents Incorporated by Reference	Portions of the 2022 Proxy Statement of Aerojet Rocketdyne Holdings, Inc. relating to its annual meeting of stockholders are incorporated by reference into Part III of this Report.
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0000040888