Sunoco Logistics Partners LP said on Monday it would buy Energy Transfer Partners LP in a deal valued at $19.93 billion.

Sunoco Logistics said ETP shareholders would get 1.5 Sunoco units for each ETP share they own, which works out to about $39.30 per share, a slight discount to the stock's Friday close of $39.37.

ETP owns about 21 pct of Sunoco Logistics, according to Thomson Reuters data.

Sunoco Logistics' general partner is a unit of ETP.