Consolidated Statements of Comprehensive Income (LLC) Consolidated Statements of Comprehensive Income (LLC) (Parenthetical) (MidAmerican Funding, LLC and Subsidiaries [Domain], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
MidAmerican Funding, LLC and Subsidiaries [Domain]
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	$ 2	$ 0	$ 2
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	$ 4	$ (3)	$ 11