Dominion Energy together with its subsidiaries produces and transports energy in the United States. It is a major energy company engaged in regulated and non-regulated electricity distribution, generation and transmission businesses. In addition, it sells electricity at wholesale prices to rural electric cooperatives, municipalities and through wholesale electricity markets. Dominion has a portfolio of nearly 27,100 MW of generating capacity, 14,800 miles of natural gas transmission, gathering, storage and distribution pipeline, as well as 6,600 miles of electric transmission and distribution lines. The company operates the nation's largest underground natural gas storage systems, with an approximate capacity of 1 trillion cubic feet (Tcf). It serves nearly 7.5 million electric or natural gas customers across 18 states.