Risk Management and Hedging Activities (MEC) Not Designated as Hedging Contracts - Nonregulated (Details) - MidAmerican Energy Company [Member] - Commodity Contract [Member] - Not Designated as Hedging Instrument [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 1	$ 1	$ 1	$ 13
Nonregulated operating revenue
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	1	1	4	(8)
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	1	0	2	0
Nonregulated cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ (1)	$ 0	$ (5)	$ 21