Employee Benefit Plans (MEC) Level 3 Rollforward (Details) (MidAmerican Energy Company and Subsidiaries [Member], United States Pension Plans of US Entity, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	$ 643		$ 555		$ 546
Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	26	[1]	24	[1]
Real Estate Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	26		24
Real Estate Funds [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets	24	[1]	17		15
Actual return on plan assets still held at period end	2		4		2
Defined Benefit Plan, Purchases, Sales, and Settlements	0		3		0
Defined Benefit Plan, Fair Value of Plan Assets	$ 26	[1]	$ 24	[1]	$ 17

[1] (1)Refer to Note 14 for additional discussion regarding the three levels of the fair value hierarchy.