XCEL ENERGY INC.
Electricity customers: 3.4 million
Territory: Minnesota, North Dakota, South Dakota, Wisconsin, Michigan, Colorado, New Mexico, Texas.
2011 electric revenue: $8.76 billion
Ownership: Publicly traded
MIDAMERICAN ENERGY HOLDINGS CO.*(U.S. regulated electric business units, MidAmerican Energy Co. and PacifiCorp)
Electricity customers: 2.4 million
Territory: Iowa, Illinois, South Dakota (MidAmerican Energy Co.); Oregon, Washington, Utah, Wyoming, Idaho, California (PacifiCorp).
2011 electric revenue: $6.24 billion
Headquarters: Des Moines (MidAmerican Energy Co. and MidAmerican Energy Holdings Co.); Portland, Ore. (PacifiCorp)
Ownership: Part of the publicly traded holding company Berkshire Hathaway, headed by Warren Buffett.
* Regulated electric utilities only; company also has unregulated businesses.