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Income Taxes (MEC) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
MidAmerican Energy Company and Subsidiaries [Member]
       
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]        
Federal statutory income tax rate 35.00% 35.00% 35.00% 35.00%
Income tax credits (52.00%) (29.00%) (52.00%) (28.00%)
State income tax, net of federal income tax benefit 8.00% 6.00% 8.00% 7.00%
Income tax method change 0.00% 0.00% (8.00%) 0.00%
Effects of ratemaking (12.00%) (7.00%) (13.00%) (6.00%)
Other, net (1.00%) 4.00% (1.00%) 0.00%
Effective income tax rate (22.00%) 9.00% (31.00%) 8.00%
Production Tax Credit Carryforwards [Abstract]        
Years eligible for renewable energy production tax credit     10 years  
Income tax method change [Abstract]        
Income tax method change     $ 18