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Change In Asset Retirement Obligations (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
MidAmerican Energy Company and Subsidiaries [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 293	$ 220
Change in estimate costs	0	50
Additions	10	10
Retirements	(1)	0
Accretion	16	13
Ending balance	318	293
Reflected as: [Abstract]
Asset retirement obligations	318	293
Total ARO liability	$ 318	$ 293

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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