Risk Management and Hedging Activities (MEC) Not Designated As Hedging Contracts - Nonregulated (Details) (MidAmerican Energy Company and Subsidiaries [Member], Commodity Contract [Member], Not Designated as Hedging Instrument [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ 4	$ 5	$ 8
Nonregulated operating revenue [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	8	18	20
Regulated cost of gas sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	0	0	3
Nonregulated cost of sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Net	$ (4)	$ (13)	$ (15)