Significant Accounting Policies - Additional Information (Details) - USD ($)		3 Months Ended	6 Months Ended
		Sep. 30, 2024	Sep. 30, 2024	Mar. 31, 2024	Jan. 11, 2024
Accounting Policies [Line Items]
Sponsor's fee rate			0.19%
Accounts payable		$ 65,617	$ 65,617	$ 21
Sponsor's fee	[1]	192,723	368,406
Waiver and reimbursement	[1]	69,438	245,121
Net investment loss	[1]	(123,285)	$ (123,285)
Franklin Bitcoin ETF [Member]
Accounting Policies [Line Items]
Sponsor's fee rate			0.19%
Accounts payable		65,617	$ 65,617	$ 21
Sponsor's fee	[1]	192,723	368,406
Waiver and reimbursement	[1]	69,438	245,121
Net investment loss	[1]	(123,285)	(123,285)
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member]
Accounting Policies [Line Items]
Amount of expenses agreed to be borne by the counterparty		500,000	500,000
Other non recurring expenses threshold limit above which shall be borne by the fund		500,000	500,000
Percentage of sponser fee before waiver					0.19%
Accounts payable					$ 21
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member] | Franklin Bitcoin ETF [Member]
Accounting Policies [Line Items]
Amount of expenses agreed to be borne by the counterparty		500,000	500,000
Other non recurring expenses threshold limit above which shall be borne by the fund		500,000	500,000
Percentage of sponser fee before waiver					0.19%
Accounts payable					$ 21
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member] | Minimum [Member]
Accounting Policies [Line Items]
Amount of expenses agreed to be borne by the counterparty		500,000	500,000
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member] | Minimum [Member] | Franklin Bitcoin ETF [Member]
Accounting Policies [Line Items]
Amount of expenses agreed to be borne by the counterparty		500,000	500,000
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member] | January 12, 2024 to August 2, 2024 [Member]
Accounting Policies [Line Items]
Initial value of the funds assets on the basis of which fees is determined		10,000,000,000	10,000,000,000
Sponsor [Member] | Ordinary Fees And Expenses Incurred By The Fund [Member] | January 12, 2024 to August 2, 2024 [Member] | Franklin Bitcoin ETF [Member]
Accounting Policies [Line Items]
Initial value of the funds assets on the basis of which fees is determined		$ 10,000,000,000	$ 10,000,000,000

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