Risk Management and Hedging Activities (MEC) Designated as Hedging Contracts (Details) (MidAmerican Energy Company [Member], Designated as Hedging Instrument [Member], Commodity Contract [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
MidAmerican Energy Company [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Beginning balance	$ 32	$ 43
Changes in fair value recognized in OCI	(25)	38
Net losses reclassified to nonregulated cost of sales	(5)	(13)
Ending balance	2	68
Cash Flow Hedge Ineffectiveness is Immaterial	insignificant	insignificant
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 0