Investment in Bitcoin - Schedule of Changes in Quantity of Bitcoin Held (Details)		3 Months Ended	6 Months Ended
		Sep. 30, 2024 USD ($) BTC shares	Sep. 30, 2024 USD ($) BTC shares
Investment Holdings, Other than Securities [Line Items]
Beginning balance of fair value	[1]		$ 341,901,126
Net realized gain (loss) from bitcoin sold for the redemption of shares	[2]	$ (1,325,741)	(1,156,994)
Net change in unrealized appreciation (depreciation) on investment in bitcoin	[2]	4,121,057	(32,337,968)
Ending balance of fair value	[1]	$ 452,356,258	$ 452,356,258
Bitcoin [Member]
Investment Holdings, Other than Securities [Line Items]
Beginning balance | BTC	[2]	5,886.9982	4,842.9986
Beginning balance of fair value	[2]	$ 373,054,955	$ 341,901,126
Bitcoin purchased for the creation of Shares (in shares) | shares	[2]	1,768.8331	3,392.8311
Bitcoin purchased for the creation of Shares	[2]	$ 107,983,297	$ 209,726,374
Bitcoin sold for the redemption of Shares (in shares) | shares	[2]	(550.9655)	(1,130.9639)
Bitcoin sold for the redemption of Shares	[2]	$ (31,419,621)	$ (65,718,591)
Principal on bitcoin sales to pay expenses (in shares) | shares	[2]	(1.017)	(1.017)
Principal on bitcoin sales to pay expenses	[2]	$ (57,689)	$ (57,689)
Net realized gain (loss) from bitcoin sold for the redemption of shares	[2]	(1,325,741)	(1,156,994)
Net change in unrealized appreciation (depreciation) on investment in bitcoin	[2]	$ 4,121,057	$ (32,337,968)
Ending Balance | BTC	[2]	7,103.8488	7,103.8488
Ending balance of fair value	[2]	$ 452,356,258	$ 452,356,258
Franklin Bitcoin ETF [Member]
Investment Holdings, Other than Securities [Line Items]
Beginning balance of fair value	[1]		341,901,126
Net realized gain (loss) from bitcoin sold for the redemption of shares	[2]	(1,325,741)	(1,156,994)
Net change in unrealized appreciation (depreciation) on investment in bitcoin	[2]	4,121,057	(32,337,968)
Ending balance of fair value	[1]	$ 452,356,258	$ 452,356,258
Franklin Bitcoin ETF [Member] | Bitcoin [Member]
Investment Holdings, Other than Securities [Line Items]
Beginning balance | BTC	[2]	5,886.9982	4,842.9986
Beginning balance of fair value	[2]	$ 373,054,955	$ 341,901,126
Bitcoin purchased for the creation of Shares (in shares) | shares	[2]	1,768.8331	3,392.8311
Bitcoin purchased for the creation of Shares	[2]	$ 107,983,297	$ 209,726,374
Bitcoin sold for the redemption of Shares (in shares) | shares	[2]	(550.9655)	(1,130.9639)
Bitcoin sold for the redemption of Shares	[2]	$ (31,419,621)	$ (65,718,591)
Principal on bitcoin sales to pay expenses (in shares) | shares	[2]	(1.017)	(1.017)
Principal on bitcoin sales to pay expenses	[2]	$ (57,689)	$ (57,689)
Net realized gain (loss) from bitcoin sold for the redemption of shares	[2]	(1,325,741)	(1,156,994)
Net change in unrealized appreciation (depreciation) on investment in bitcoin	[2]	$ 4,121,057	$ (32,337,968)
Ending Balance | BTC	[2]	7,103.8488	7,103.8488
Ending balance of fair value	[2]	$ 452,356,258	$ 452,356,258

[1] Cost of investment in bitcoin: $423,417,042 at September 30, 2024 and $280,623,942 at March 31, 2024.

[2] No comparative period presented as the Fund’s operations commenced on January 11, 2024.