Short-Term Debt and Credit Facilities - MidAmerican Funding (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	[1]	$ 9,051	$ 6,345
MidAmerican Funding, LLC and Subsidiaries [Domain] | Unsecured 364-day credit facility, $4 million, expiring June [Member] | MHC, Inc. [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		4
Outstanding balance on credit facility		$ 0	$ 0

[1] (1)The table does not include unused credit facilities and letters of credit for investments that are accounted for under the equity method.