Income Taxes (MEC) Components of Income Tax Expense (Benefit) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
MidAmerican Energy Company and Subsidiaries [Member]
Components of Income Tax Expense (Benefit) [Line Items]
Current federal	$ (256)	$ (474)	$ (161)
Current state	(21)	(6)	(25)
Total current income tax expense (benefit)	(277)	(480)	(186)
Deferred federal	200	453	125
Deferred state	(20)	11	14
Total deferred income tax expense (benefit)	180	464	139
Investment tax credits	(2)	(1)	(2)
Income tax expense (benefit)	$ (99)	$ (17)	$ (49)