A pair of Lone Star State-based Am Law 100 firms are working on Great Plains Energy Inc.’s acquisition of Westar Energy Inc., the latest sign of consolidation in the utilities sector.

Kansas City, Missouri-based Great Plains announced Tuesday that it will buy Topeka, Kansas-based Westar in a $12.2 billion cash-and-stock deal that includes $3.6 billion in the target’s debt. The combination will create an investor-owned utility that will serve 1.5 million customers in Missouri and Kansas, while also controlling a massive Midwestern portfolio for wind generation.