Components of Accumulated Other Comprehensive Loss, Net (MEC) (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
Accumulated Other Comprehensive Loss, Net [Roll Forward]
Other comprehensive income, Unrealized losses on available-for-sale securities	$ 3	$ 1	$ 2
Other comprehensive income, Unrealized losses on cash flow hedges	7	(6)	18
Other comprehensive income (loss)	10	(5)	20
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Loss, Net [Roll Forward]
Balance, December 31, 2011, Unrealized losses on available-for-sale securities	(8)
Other comprehensive income, Unrealized losses on available-for-sale securities	3
Balance, December 31, 2012, Unrealized losses on available-for-sale securities	(5)	(8)
Balance, December 31, 2011, Unrealized losses on cash flow hedges	(26)
Other comprehensive income, Unrealized losses on cash flow hedges	7
Balance, December 31, 2012, Unrealized losses on cash flow hedges	(19)	(26)
Balance December 31, 2011, Accumulated other comprehensive loss, net	(34)
Other comprehensive income (loss)	10	(5)	20
Balance December 31, 2012, Accumulated other comprehensive loss, net	$ (24)	$ (34)