Consolidated Statements of Changes in Equity (MEC) (MidAmerican Energy Company and Subsidiaries [Member], USD $) In Millions, unless otherwise specified	MidAmerican Energy Company and Subsidiaries [Member] USD ($)	MidAmerican Energy Company and Subsidiaries [Member] Common Stock [Member] USD ($)	MidAmerican Energy Company and Subsidiaries [Member] Retained Earnings [Member] USD ($)	MidAmerican Energy Company and Subsidiaries [Member] Accumulated Other Comprehensive Income (Loss) [Member] USD ($)	MidAmerican Energy Company and Subsidiaries [Member] Preferred Securities [Member] USD ($)	MidAmerican Energy Company and Subsidiaries [Member] Noncontrolling Interest [Member] USD ($)
Balance at Dec. 31, 2009	$ 2,960	$ 561	$ 2,417	$ (49)	$ 30	$ 1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	357		357			0
Other comprehensive income (loss)	20			20		0
Repurchase of preferred securities	(2)	1			(3)
Common dividends	(375)		(375)
Preferred dividends	(1)		(1)
Balance at Dec. 31, 2010	2,959	562	2,398	(29)	27	1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	74
Balance at Mar. 31, 2011
Balance at Dec. 31, 2010	2,959		2,398	(29)		1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	319		319			0
Other comprehensive income (loss)	(5)			(5)		0
Preferred dividends	(1)		(1)
Balance at Dec. 31, 2011	3,272	562	2,716	(34)	27	1
Balance at Sep. 30, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	89
Balance at Dec. 31, 2011	3,272	562			27
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	74
Balance at Mar. 31, 2012
Balance at Dec. 31, 2011	3,272	562	2,716	(34)	27	1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	355		355			0
Other comprehensive income (loss)	10			10		0
Preferred dividends	(1)		(1)
Disposition of subsidiary	(1)					(1)
Balance at Dec. 31, 2012	3,635	562	3,070	(24)	27	0
Balance at Sep. 30, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	60
Balance at Dec. 31, 2012	$ 3,635	$ 562			$ 27