S-K 1602(b)(6) Prospectus Summary, Sponsor Compensation	Feb. 23, 2026 USD ($) $ / shares shares
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 100,000
Dune Acquisition Holdings III LLC [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 20,000
Securities Issued or to be Issued, Shares (in Shares) \| shares	800,000
Price Paid or to be Paid for Securities, Per Share (in Dollars per share) \| $ / shares	$ 0.001
Dune Acquisition Holdings III LLC [Member] \| Common Class B [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 25,000
Securities Issued or to be Issued, Shares (in Shares) \| shares	6,000,000
Dune Acquisition Holdings III LLC [Member] \| Private Placement Warrants [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 1,880,000
Securities Issued or to be Issued, Shares (in Shares) \| shares	1,880,000
Dune Acquisition Holdings III LLC [Member] \| Working Capital [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 1,500,000
Dune Acquisition Holdings III LLC [Member] \| Warrants [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Per Share (in Dollars per share) \| $ / shares	$ 1
Sponsor [Member] \| Private Placement Warrants [Member]
SPAC Prospectus Summary, Sponsor Compensation [Line Items]
Price Paid or to be Paid for Securities, Total Amount	$ 1,000,000
Securities Issued or to be Issued, Shares (in Shares) \| shares	1,000,000
Price Paid or to be Paid for Securities, Per Share (in Dollars per share) \| $ / shares	$ 1

Dune Acquisition Corp III S-1