Risk Management and Hedging Activities (MEC) Not Designated as Hedging Contracts (Details) (MidAmerican Energy Company [Member], Not Designated as Hedging Instrument [Member], Commodity Contract [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
MidAmerican Energy Company [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Regulatory Assets (Liabilities), Net, Derivatives [Roll Forward]
Beginning balance	$ 24	$ 60	$ 45	$ 73
Changes in fair value recognized in net regulatory assets	1	1	0	11
Net gains reclassified to operating revenue	0	7	3	20
Net gains reclassified to cost of fuel, energy and capacity	0	0	0	1
Net losses reclassified to cost of gas sold	(2)	(5)	(25)	(42)
Ending balance	$ 23	$ 63	$ 23	$ 63