Exelon Corp. has formally applied to acquire Pepco Holdings.

Exelon filed the application Tuesday with the Maryland Public Service Commission. The deal will combine Exelon Corp.'s electric and gas utilities BGE, ComEd and PECO with Pepco's Atlantic City Electric, Delmarva Power and its namesake utility.

The combined utility businesses will serve approximately 10 million customers.

The proposed deal was announced April 30.