Related Party Transactions (LLC) (Details) (MidAmerican Funding, LLC and Subsidiaries [Domain], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Related Party Transactions [Line Items]
Note payable to affiliate	$ 246	$ 231
Maximum Debt to Capitalization Ratio	0.67
Minumum Interest Coverage Ratio	2.2
Affiliated Entity [Member]
Related Party Transactions [Line Items]
Related Party Transaction, Expense Reimbursement	42	44	43
Due from Affiliate, Current	7	7
Due to Affiliate, Current	7	11
Due from Affiliate, Noncurrent	16	17
Due to Affiliate, Noncurrent	20	13
MEHC [Member]
Related Party Transactions [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	7	11	15
MEHC [Member] | MHC, Inc. [Member] | Line of Credit [Member] | Revolving Credit Arrangement, $300 million [Member]
Related Party Transactions [Line Items]
Line of Credit Arrangement Offered to Affiliate, Maximum Amount Available	300
Note payable to affiliate	246	231
Debt, Weighted Average Interest Rate	0.465%	0.521%
MEHC [Member] | MHC, Inc. [Member] | Line of Credit [Member] | Revolving Credit Arrangement, $100 million [Member]
Related Party Transactions [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	100
Notes Receivable, Related Parties, Current	0	0
Debt, Weighted Average Interest Rate	0.00%	0.00%
Northern Natural Gas [Member]
Related Party Transactions [Line Items]
Related Party Transaction, Purchases from Related Party	$ 59	$ 59	$ 58