S-K 1603(a)(9) Restrictions on Selling Securities	Feb. 24, 2026
Founder Shares [Member]
Spac Sponsor And Affiliates Information Restrictions On Sale Of Spac Securities Line Items
SPAC Sponsor, Description of Expiration Dates of Restrictions [Text Block]	The earlier of (A) one year after the completion of our initial business combination or earlier if, subsequent to our initial business combination, the closing price of the Class A ordinary shares equals or exceeds $12.00 per share (as adjusted for share sub-divisions, share capitalizations, reorganizations, recapitalizations and the like) for any 20 trading days within any 30-trading day period commencing at least 150 days after our initial business combination and (B) the date following the completion of our initial business combination on which we complete a liquidation, merger, share exchange or other similar transaction that results in all of our shareholders having the right to exchange their Class A ordinary shares for cash, securities or other property.
SPAC Sponsor, Persons and Entities Subject to Restrictions	Illumination Acquisition 1 Sponsor LLC, officers, directors and director nominees
SPAC Sponsor, Description of Exceptions to Restrictions [Text Block]	Transfers permitted (a) to our officers, directors, advisors or consultants, any affiliate or family member of any of our officers, directors, advisors or consultants, any members or partners of the sponsor and their respective affiliates and funds and accounts advised by such members or partners, any affiliates of the sponsor, or any employees of such affiliates; (b) in the case of an individual, as a gift to such person’s immediate family or to a trust, the beneficiary of which is a member of such person’s immediate family, an affiliate of such person or to a charitable organization; (c) in the case of an individual, by virtue of laws of descent and distribution upon death of such person; (d) in the case of an individual, pursuant to a qualified domestic relations order; (e) by private sales or transfers made at or prior to the consummation of an initial business combination at prices no greater than the price at which the shares or units were originally purchased; (f) pro rata distributions from our sponsor to its members, partners or shareholders pursuant to our sponsor’s limited liability company agreement or other charter documents; (g) by virtue of the laws of the Cayman Islands or our sponsor’s limited liability company agreement upon dissolution of our sponsor; (h) in the event of our liquidation prior to our consummation of our initial business combination; (i) in the event that, subsequent to our consummation of an initial business combination, we complete a liquidation, merger, share exchange or other similar transaction which results in all of our shareholders having the right to exchange their Class A ordinary shares for cash, securities or other property; or (j) to a nominee or custodian of a person or entity to whom a transfer would be permissible under clauses (a) through (g); provided, however, that in the case of clauses (a) through (g) and clause (j) these permitted transferees must enter into a written agreement agreeing to be bound by these transfer restrictions and the other restrictions contained in the letter agreements.
Private Placement Units [Member]
Spac Sponsor And Affiliates Information Restrictions On Sale Of Spac Securities Line Items
SPAC Sponsor, Description of Expiration Dates of Restrictions [Text Block]	30 days after the completion of our initial business combination
SPAC Sponsor, Persons and Entities Subject to Restrictions	Illumination Acquisition 1 Sponsor LLC, officers, directors and director nominees and BTIG
SPAC Sponsor, Description of Exceptions to Restrictions [Text Block]	Same as above (other than clauses (f) and (g) with respect to the inclusion of BTIG).
Convertible Security [Member]
Spac Sponsor And Affiliates Information Restrictions On Sale Of Spac Securities Line Items
SPAC Sponsor, Description of Expiration Dates of Restrictions [Text Block]	180 days
SPAC Sponsor, Persons and Entities Subject to Restrictions	Illumination Acquisition 1 Sponsor LLC, officers, directors and director nominees and BTIG
SPAC Sponsor, Description of Exceptions to Restrictions [Text Block]	The representative in its sole discretion may release any of the securities subject to these lock-up agreements at any time without notice. Our sponsor, officers and directors are also subject to separate transfer restrictions on their founder shares and private placement units (including the securities comprising such units and the Class A ordinary shares issuable upon exercise of the private placement warrants) pursuant to the letter agreement described in the immediately preceding paragraphs.

Illumination Acquisition Corp. I S-1/A