Combined Schedules of Investments		Dec. 31, 2025 USD ($) Bitcoin	Mar. 31, 2025 USD ($) Bitcoin
Combined Schedule of Investments [Abstract]
Quantity of Bitcoin (in Bitcoin) | Bitcoin		5,727.6529	4,956.3464
Total investments, Cost		$ 426,448,438	$ 313,983,408
Total investments, Fair Value	[1]	$ 500,957,877	$ 411,158,674
Total investments, Fair Value as a % of Net Assets		100.02%	100.07%
Other assets less liabilities, Fair Value		$ (83,339)	$ (301,331)
Other assets less liabilities, Fair Value as a % of Net Assets		(0.02%)	(0.07%)
Net assets		$ 500,874,538	$ 410,857,343
Net assets, Fair Value as a % of Net Assets		100.00%	100.00%
Franklin Bitcoin ETF [Member]
Combined Schedule of Investments [Abstract]
Quantity of Bitcoin (in Bitcoin) | Bitcoin		5,727.6529	4,956.3464
Total investments, Cost		$ 426,448,438	$ 313,983,408
Total investments, Fair Value	[1]	$ 500,957,877	$ 411,158,674
Total investments, Fair Value as a % of Net Assets		100.02%	100.07%
Other assets less liabilities, Fair Value		$ (83,339)	$ (301,331)
Other assets less liabilities, Fair Value as a % of Net Assets		(0.02%)	(0.07%)
Net assets		$ 500,874,538	$ 410,857,343
Net assets, Fair Value as a % of Net Assets		100.00%	100.00%
Bitcoin [Member]
Combined Schedule of Investments [Abstract]
Quantity of Bitcoin (in Bitcoin) | Bitcoin		5,727.6529	4,956.3464
Total investments, Cost		$ 426,448,438	$ 313,983,408
Total investments, Fair Value		$ 500,957,877	$ 411,158,674
Total investments, Fair Value as a % of Net Assets		100.02%	100.07%
Bitcoin [Member] | Franklin Bitcoin ETF [Member]
Combined Schedule of Investments [Abstract]
Quantity of Bitcoin (in Bitcoin) | Bitcoin		5,727.6529	4,956.3464
Total investments, Cost		$ 426,448,438	$ 313,983,408
Total investments, Fair Value		$ 500,957,877	$ 411,158,674
Total investments, Fair Value as a % of Net Assets		100.02%	100.07%

[1] Cost of investment in bitcoin: $426,448,438 at December 31, 2025 and $313,983,408 at March 31, 2025.