Kinder Morgan Energy Partners will sell certain assets in the Rocky Mountains area to privately held Tallgrass Energy Partners for $1.8 billion in cash to secure regulatory approval for its $23 billion buy of rival El Paso.

Kinder Morgan said in March that it had reached an agreement with the Federal Trade Commission to divest certain assets in the Rockies.

Including debt, the deal is valued at $3.3 billion.

The company said it will divest its Interstate gas transmission assets, trailblazer pipeline company, the Casper-Douglas natural gas processing and West Frenchie Draw treating facilities in Wyoming and a 50 percent interest in the Rockies express pipeline.