Cover - shares	6 Months Ended
Jun. 30, 2026	Aug. 11, 2026
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2026
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2026
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-42503
Entity Registrant Name	K&F GROWTH ACQUISITION CORP. II
Entity Central Index Key	0002029976
Amendment Flag	false
Entity Incorporation, State or Country Code	E9
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	1219 Morningside Drive
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Manhattan Beach
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90266
City Area Code	310
Local Phone Number	545-9265
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	true
Units, each consisting of one Class A Ordinary Share and one Right
Document Information [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A Ordinary Share and one Right
Trading Symbol	KFIIU
Security Exchange Name	NASDAQ
Class A Ordinary Shares, par value $0.0001 per share
Document Information [Line Items]
Title of 12(b) Security	Class A Ordinary Shares, par value $0.0001 per share
Trading Symbol	KFII
Security Exchange Name	NASDAQ
Rights, each Right entitling the holder to receive one-fifteenth (1/15) of one Class A Ordinary Share
Document Information [Line Items]
Title of 12(b) Security	Rights, each Right entitling the holder to receive one-fifteenth (1/15) of one Class A Ordinary Share
Trading Symbol	KFIIR
Security Exchange Name	NASDAQ
Class A Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		29,672,727
Class B Ordinary Shares
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		9,583,333

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