Boeing and Delta Air Lines today announced an order for 100 B737-900ERs worth $8.5 billion at list prices. The order was placed as part of Delta’s fleet renewal effort to replace Airbus A320s acquired from its 2008 merger with Northwest Airlines, as well as older Boeing 757s and 767s.

Delta will begin taking deliveries of the 180-seat, extended-range 737-900ERs in the second half of 2013. It will receive 12 aircraft that year, then 19 per year from 2014 to 2017 and the remaining 12 in 2018. “Each aircraft has committed long-term financing,” the airline said.

The 737-900ER, powered by CFM56-7B engines, is the latest in Boeing’s Next Generation 737 series; it has a range of 3,200 nm. All of the Delta aircraft will feature Boeing’s new “Sky Interior” with an LED cabin lighting system.

Delta said the size and timing of the order will allow it to maintain its annual capital expenditures at $1.2 billion to $1.4 billion over the next three years and will not affect the airline’s $1.2 billion in capital expenditures projected this year. The Atlanta-based airline is halfway through a $2 billion, three-year investment in new aircraft, facilities and technology.