Employee Benefit Plans (MEC) Plan Amendments (Details) (MidAmerican Energy Company [Member], United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
MidAmerican Energy Company [Member] | United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	$ (2)	$ (3)	$ (4)