Document and Entity Information Document (USD $)	12 Months Ended
	Dec. 31, 2012	Jan. 31, 2013	Jun. 30, 2012
Entity Information [Line Items]
Document Period End Date	Dec. 31, 2012
Document Type	10-K
Document Fiscal Year Focus	2012
Amendment Flag	false
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 0
Entity Registrant Name	MIDAMERICAN ENERGY COMPANY
Entity Central Index Key	0000928576
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		70,980,203
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
MidAmerican Funding, LLC and Subsidiaries [Domain]
Entity Information [Line Items]
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Public Float			$ 0
Entity Registrant Name	MIDAMERICAN FUNDING, LLC
Entity Central Index Key	0001098296
Entity Filer Category	Non-accelerated Filer
Entity Voluntary Filers	Yes
Entity Current Reporting Status	Yes