Duke Energy is buying Piedmont Natural Gas for about $4.9 billion in cash.The companies are key partners in the $5 billion Atlantic Coast Pipeline, which will be the first major natural gas pipeline to serve Eastern North Carolina.Piedmont shareholders will receive $60 in cash for each share of common stock, a 42 percent premium to Friday's closing price. Duke Energy Corp. will also assume approximately $1.8 billion in Piedmont debt.Piedmont Natural Gas Co. will keep its name and maintain its headquarters in Charlotte, and one of its directors will join Duke's board.Officials said customers of both utilities will notice little change."You're going to get a Piedmont bill. You're going to get a Duke bill. If you have an outage or customer service issue, you're going to call the same numbers moving forward and that's not going to change once the deal is complete, because Piedmont will still be Piedmont. They're just going to be a part of the Duke Energy family," Duke Energy spokesman Ryan Mosier said.Both companies unanimously approved the transaction, which is targeted to close by the end of 2016. It still needs approval from Piedmont shareholders and the North Carolina Utilities Commission.