Investments and Nonregulated Property, Net (LLC) (Details) (MidAmerican Funding, LLC and Subsidiaries [Domain], USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
MidAmerican Funding, LLC and Subsidiaries [Domain]
Investments and Nonregulated Property, Net [Line Items]
Nuclear decommissioning trust	$ 337	$ 306
Rabbi trusts	173	161
Auction rate securities	21	16
Nonregulated property, net of accumulated depreciation of $14 and $13, respectively	22	28
Coal transportion property, net of accumulated depreciation of $- and $4, respectively	0	8
Other	8	9
Total	561	528
Nonregulated property accumulated depreciation	14	13
Coal transportation property accumulated depreciation	$ 0	$ 4