Fair Value Measurements (MEC) Level 3 (Details) (MidAmerican Energy Company [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Commodity Derivative [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 0		$ 22
Changes included in earnings	3	[1]	10	[1]
Changes in fair value recognized in other comprehensive income	(3)		(3)
Changes in fair value recognized in net regulatory assets	1		8
Settlements	(3)		(14)
Ending balance	(2)		23
Net unrealized gains (losses) included in earnings	(3)		7
Auction rate securities [Member]
Fair Value, Assets and Liabilities, Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	21		16
Changes included in earnings	0	[1]	0	[1]
Changes in fair value recognized in other comprehensive income	1		1
Changes in fair value recognized in net regulatory assets	0		0
Settlements	0		0
Ending balance	$ 22		$ 17

[1] Changes included in earnings are reported as nonregulated operating revenue on the Statements of Operations. For commodity derivatives held as of March 31, 2013 and 2012, net unrealized (losses) gains included in earnings for the three-month periods ended March 31, 2013 and 2012, totaled $(3) million and $7 million, respectively.