MidAmerican is owned by Berkshire Hathaway, the investment giant controlled by billionaire Warren Buffett.
The New York Times reported Thursday the deal includes the transfer of about $4.5 billion in debt. The purchase price, however, is set at a 23 percent premium over NV Energy's closing share price Wednesday.
MidAmerican serves 7.1 million residents in 10 states. NV Energy, by contrast, serves 1.3 million Nevada residents with both natural gas and energy, the Times said.
Buffett said he was banking on a resurgence in Nevada, one of the states bruised the most by the economic downturn.
"This is a great fit for Berkshire Hathaway, and we are pleased to make a long-term investment in Nevada's economy," Buffett said.
"Through MidAmerican, we have found in NV Energy a great company with similar values, outstanding assets, and a superb management team," he said.
Buffett bought MidAmerican in 2000, to acquire an initial inroad into the energy sector, he has said.