Risk Management and Hedging Activities (MEC) Derivative Contract Volumes (Details) (MidAmerican Energy Company and Subsidiaries [Member], Commodity Contract [Member])	Dec. 31, 2012 MWh	Dec. 31, 2011 MWh
Electricity purchases (in megawatt hours) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, Nonmonetary Notional Amount	5,000,000	8,000,000
Natural gas purchases (in decatherms) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, Nonmonetary Notional Amount	36,000,000	62,000,000
Fuel purchases (in gallons) [Member]
Notional Amounts of Outstanding Derivative Positions [Line Items]
Derivative, Nonmonetary Notional Amount	0	2,000,000