You may need an embassy visa for Brunei if you have an Indonesian passport
Visa options for Brunei
Visitor visa is required for trips longer than 14 days for Tourism
Travelers need a visa to visit Brunei for Tourism for more than 14 days. Travelers do not need a visa if staying for 14 days or less. A paper or embassy visa is the only visa available for travelers visiting Brunei. The visa is typically a stamp or sticker added to the passport. Travelers must obtain this visa from a local embassy, consulate or visa center before traveling.
This is not offered by sherpa°.
Apply on the government site.