Fair Value Measurements (MEC) Level 3 (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
Commodity Derivatives [Member]
Fair Value, Assets (Liabilities), Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 22		$ 14		$ 21
Changes included in earnings	5	[1]	23	[1]	14	[1]
Changes in fair value recognized in other comprehensive income	0		(3)		0
Changes in fair value recognized in net regulatory assets	(3)		12		5
Sales	0		0		0
Settlements	(24)		(25)		(29)
Transfers To Level 2	0		0		3
Transfers From Level 2	0		1		0
Ending balance	0		22		14
Net unrealized gains (losses) included earnings	0		15		8
Debt Securities [Member]
Fair Value, Assets (Liabilities), Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	16		20		16
Changes included in earnings	0	[1]	0	[1]	0	[1]
Changes in fair value recognized in other comprehensive income	5		1		4
Changes in fair value recognized in net regulatory assets	0		0		0
Sales	0		(5)		0
Settlements	0		0		0
Transfers To Level 2	0		0		0
Transfers From Level 2	0		0		0
Ending balance	$ 21		$ 16		$ 20

[1] Changes included in earnings are reported as nonregulated operating revenue on the Consolidated Statements of Operations. Net unrealized gains included in earnings for the years ended December 31, 2012, 2011 and 2010, related to commodity derivatives held at December 31, 2012 , 2011 and 2010, totaled $- million, $15 million and $8 million, respectively.