Income Taxes (LLC) Components of Income Tax Expense (Benefit) (Details) (MidAmerican Funding, LLC and Subsidiaries [Domain], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
MidAmerican Funding, LLC and Subsidiaries [Domain]
Components of Income Tax Expense (Benefit) [Line Items]
Current federal	$ (260)	$ (480)	$ (172)
Current state	(23)	(8)	(31)
Total current income tax expense (benefit)	(283)	(488)	(203)
Deferred federal	198	452	130
Deferred state	(21)	11	14
Total deferred income tax expense (benefit)	177	463	144
Investment tax credits	(2)	(1)	(2)
Total income tax expense (benefit)	$ (108)	$ (26)	$ (61)