Financial Highlights - Summary of Per Share Performance (Details) - $ / shares		3 Months Ended	6 Months Ended
		Sep. 30, 2024	Sep. 30, 2024
Net asset value per Share, beginning of period	[1]	$ 36.75	$ 40.95
Net investment loss	[1],[2]	(0.01)	(0.01)
Net realized and unrealized gain (loss) on investment in bitcoin	[1]	0.18	(4.02)
Net change in net assets from operations	[1],[3]	0.17	(4.03)
Net asset value per Share, end of period	[1]	$ 36.92	$ 36.92
Total return, at net asset value	[1],[4],[5]	0.46%	(9.84%)
Ratio to average net assets
Net investment loss	[1],[6]	(0.12%)	(0.06%)
Gross expenses	[1],[6]	0.19%	0.19%
Net expenses	[1],[6]	0.12%	0.06%
Franklin Bitcoin ETF [Member]
Net asset value per Share, beginning of period	[1]	$ 36.75	$ 40.95
Net investment loss	[1],[2]	(0.01)	(0.01)
Net realized and unrealized gain (loss) on investment in bitcoin	[1]	0.18	(4.02)
Net change in net assets from operations	[1],[3]	0.17	(4.03)
Net asset value per Share, end of period	[1]	$ 36.92	$ 36.92
Total return, at net asset value	[1],[4],[5]	0.46%	(9.84%)
Ratio to average net assets
Net investment loss	[1],[6]	(0.12%)	(0.06%)
Gross expenses	[1],[6]	0.19%	0.19%
Net expenses	[1],[6]	0.12%	0.06%

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

[2] Calculated using average Shares outstanding.

[3] The amount shown for a share outstanding may not agree with the change in the aggregate gains and losses on investment for the period because of the timing of transactions in the Fund’s shares in relation to fluctuating market values for the Fund’s underlying investment.

[4] Percentage is not annualized.

[5] Total Return at NAV is calculated assuming an initial investment made at the NAV at the beginning of the period, and redemption of Shares at NAV on the last day of the period. Total Return at NAV as shown above includes adjustments in accordance with U.S. GAAP.

[6] Annualized.