v3.26.1
INVESTMENT IN BITCOIN - Changes in Quantity of Bitcoin Held (Details) - Franklin Bitcoin ETF [Member]
3 Months Ended
Jun. 30, 2026
USD ($)
Bitcoin
Jun. 30, 2025
USD ($)
Bitcoin
INVESTMENT IN BITCOIN [Abstract]    
Beginning Balance, Quantity (in Bitcoin) | Bitcoin 6,302.8336 4,956.3464
Beginning Balance, Amount $ 429,409,784 [1] $ 411,158,674
Bitcoin purchased for the creation of Shares, Quantity (in Bitcoin) | Bitcoin 86.6972 608.151
Bitcoin purchased for the creation of Shares, Amount $ 5,799,402 $ 55,501,643
Bitcoin sold for the redemption of Shares, Quantity (in Bitcoin) | Bitcoin (722.4968) (405.4311)
Bitcoin sold for the redemption of Shares, Amount $ (53,852,604) $ (35,230,580)
Principal on bitcoin sales to pay expenses, Quantity (in Bitcoin) | Bitcoin (3.0177) (3.7004)
Principal on bitcoin sales to pay expenses, Amount $ (218,027) $ (301,334)
Net realized gain (loss) from bitcoin sold for the redemption of Shares and sold to pay expenses, Amount (396,857) 9,019,211
Net change in unrealized appreciation (depreciation) on investment in bitcoin, Amount $ (45,989,896) $ 119,518,907
Ending Balance, Quantity (in Bitcoin) | Bitcoin 5,664.0163 5,155.3659
Ending Balance, Amount $ 334,751,802 [1] $ 559,666,521
[1] Cost of investment in bitcoin: $424,710,391 at June 30, 2026 and $473,378,477 at March 31, 2026.