Unaudited Quarterly Operating Results (MEC) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
MidAmerican Energy Company and Subsidiaries [Member]
Unaudited Quarterly Operating Results [Line Items]
Operating revenue	$ 834	$ 825	$ 709	$ 874	$ 852	$ 866	$ 804	$ 979	$ 3,242	$ 3,501	$ 3,810
Operating income	58	139	81	92	82	148	86	113	370	429	459
Net income	60	140	81	74	89	107	49	74	355	319	357
Earnings on common stock	60	140	80	74	89	107	48	74	354	318	357
Income tax benefits from tax method change			$ 18		$ 35