General (MEC) Utility Plant Depreciation Rates (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Depreciable Assets [Member]
Change in Accounting Estimate [Line Items]
Change in depreciation rates, annual impact on future years			$ 49
Change in depreciation rates, impact on current period from prior year change	12	24
Service Life [Member]
Change in Accounting Estimate [Line Items]
Change in depreciation rates, impact on period of change	12	25
Change in depreciation rates, annual impact on future years		$ 50