Risk Management and Hedging Activities (MEC) Designated As Hedging Contracts (Details) (MidAmerican Energy Company and Subsidiaries [Member], Commodity Contract [Member], Designated as Hedging Instrument [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
MidAmerican Energy Company and Subsidiaries [Member] | Commodity Contract [Member] | Designated as Hedging Instrument [Member]
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Beginning balance	$ 43	$ 34	$ 63
Net losses recognized in other comprehensive income	27	27	14
Net losses reclassified to nonregulated cost of sales	(38)	(18)	(43)
Ending balance	32	43	34
Cash flow hedge ineffectiveness	insignificant
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 21