Employee Benefit Plans (MEC) Net Periodic Benefit Cost (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	$ 14	$ 14	$ 16
Service cost	18	18	17
Interest cost	37	39	39
Expected return on plan assets	(45)	(43)	(40)
Net amortization	(4)	0	0
Net periodic benefit cost (benefit)	14	14	16
United States Pension Plans of US Entity, Defined Benefit [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	8	9	9
Net periodic benefit cost (benefit)	8	9	9
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	(4)	(1)	0
Service cost	4	4	4
Interest cost	8	10	11
Expected return on plan assets	(13)	(13)	(13)
Net amortization	3	2	2
Net periodic benefit cost (benefit)	(4)	(1)	0
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member] | MidAmerican Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	(2)	0	1
Net periodic benefit cost (benefit)	$ (2)	$ 0	$ 1