Preferred Securities (MEC) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
MidAmerican Energy Company and Subsidiaries [Member]
Class of Stock [Line Items]
Preferred Stock, Redemption Amount	$ 28	$ 28
Preferred Stock, Value, Outstanding	27	27
Preferred Stock, Annual Dividend Requirement	$ 1