Risk Management and Hedging Activities (MEC) Derivative Contract Volumes (Details) (MidAmerican Energy Company [Member], Commodity Contract [Member])	Jun. 30, 2014 MWh	Dec. 31, 2013 MWh
Electricity purchases (in megawatt hours) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, Nonmonetary Notional Amount	7,000,000	5,000,000
Natural gas purchases (in decatherms) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, Nonmonetary Notional Amount	16,000,000	21,000,000