Employee Benefit Plans (MEC) (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 4
Interest cost	8	9
Expected return on plan assets	(11)	(10)
Net amortization	3	1
Net periodic benefit cost	5	4
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest cost	2	2
Expected return on plan assets	(3)	(3)
Net amortization	(1)	0
Net periodic benefit cost	$ (1)	$ 0