Regulatory Matters (MEC) Assets (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Regulatory Assets [Line Items]
Regulatory assets	$ 876		$ 831
Regulatory assets not earning a return on investment	871		826
Deferred income taxes, net [Member]
Regulatory Assets [Line Items]
Regulatory assets	640	[1]	569	[1]
Average Remaining Life	21 years
Employee benefit plans [Member]
Regulatory Assets [Line Items]
Regulatory assets	121	[2]	101	[2]
Average Remaining Life	11 years
Unrealized loss on regulated derivative contracts [Member]
Regulatory Assets [Line Items]
Regulatory assets	50		94
Average Remaining Life	1 year
Other [Member]
Regulatory Assets [Line Items]
Regulatory assets	$ 65		$ 67
Regulatory asset amortization period years	Various

[1] Amounts primarily represent income tax benefits related to state accelerated tax depreciation and certain property-related basis differences that were previously flowed through to customers and will be included in regulated rates when the temporary differences reverse.

[2] Represents amounts not yet recognized as a component of net periodic benefit cost that are expected to be included in regulated rates when recognized.