With 230 airplanes at a list price of $21.7 billion, this deal when finalized will be the largest commercial airplane order ever in Boeing’s history by both dollar volume and total number of airplanes. Boeing and Lion Air are working to finalize details of the agreement, at which time it will be a firm order posted on the Boeing Orders and Deliveries website. Lion Air will also acquire purchase rights for an additional 150 airplanes valued at more than $14 billion if exercised at list prices.

US President Barack Obama witnessed the announcement at a ceremony today at the East Asia Summit in Bali, Indonesia.

The 737 MAX is a new engine variant of the 737 and builds on the strengths of today’s Next-Generation 737. The 737 MAX incorporates the latest-technology CFM International LEAP 1-B engines.

Airlines operating the 737 MAX will see a 10-12% fuel burn improvement over today’s most fuel efficient single-aisle airplanes and a 7% operating cost advantage over tomorrow’s competition, according to Boeing.

To date, the 737 MAX has commitments for more than 700 airplanes, while the Next-Generation 737 family has won orders for more than 6,000 airplanes and Boeing has delivered more than 3,800.

Lion Air, Indonesia’s largest private airline, currently operates or has on order a total of 178 Next-Generation 737s.