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	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive (Income) Loss, Net, Derivatives [Roll Forward]
Beginning balance	$ 30	$ (13)	$ 34	$ 11
Changes in fair value recognized in OCI	25	(21)	19	(79)
Net gains (losses) reclassified to nonregulated cost of sales	(16)	6	(14)	40
Ending balance	$ 39	$ (28)	39	(28)
Cash flow hedge ineffectiveness is immaterial	insignificant	insignificant
Gain (loss) on cash flow hedge ineffectiveness, net			1	$ 0
Cash flow hedge gain (loss) to be reclassified within twelve months			$ (22)