Summary of Significant Accounting Policies (MEC) Income Taxes (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Notes to Consolidated Financial Statements [Line Items]
Regulatory Assets, Noncurrent	$ 876		$ 831
Deferred Income Tax Charges [Member]
Notes to Consolidated Financial Statements [Line Items]
Regulatory Assets, Noncurrent	$ 640	[1]	$ 569	[1]

[1] Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously flowed through to customers and will be included in regulated rates when the temporary differences reverse.