Cover - USD ($)	11 Months Ended
	Dec. 31, 2025	Feb. 19, 2026	Jun. 30, 2025
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Financial Statement Error Correction [Flag]	false
Entity Interactive Data Current	Yes
ICFR Auditor Attestation Flag	false
Amendment Flag	false
Document Period End Date	Dec. 31, 2025
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Entity Information [Line Items]
Entity Registrant Name	Blue Acquisition Corp/Cayman
Entity Central Index Key	0002059654
Entity File Number	001-42699
Entity Tax Identification Number	98-1855000
Entity Incorporation, State or Country Code	E9
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	true
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Public Float			$ 202,055,000
Entity Contact Personnel [Line Items]
Entity Address, Address Line One	1601 Anita Lane
Entity Address, City or Town	Newport Beach
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92660-4803
Entity Phone Fax Numbers [Line Items]
City Area Code	646
Local Phone Number	543-5060
Class A Ordinary Share Units
Entity Listings [Line Items]
Title of 12(b) Security	Units, each consisting of one Class A Ordinary Share and one Right
Trading Symbol	BACCU
Security Exchange Name	NASDAQ
Common Class A
Entity Listings [Line Items]
Title of 12(b) Security	Class A Ordinary Shares, par value $0.0001 per share
Trading Symbol	BACC
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		20,892,250
Class A Ordinary Share Rights
Entity Listings [Line Items]
Title of 12(b) Security	Rights, each entitling the holder to receive one-tenth (1/10) of one Class A Ordinary Share
Trading Symbol	BACCR
Security Exchange Name	NASDAQ
Class B Ordinary Shares
Entity Listings [Line Items]
Entity Common Stock, Shares Outstanding		7,069,913