Summary of Significant Accounting Policies Income Taxes Policy (Details) - MidAmerican Energy Company [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets and Liabilities [Line Items]
Regulatory assets	$ 1,044	$ 908
Deferred Income Tax Charge [Member]
Deferred Tax Assets and Liabilities [Line Items]
Regulatory assets	$ 858	$ 730

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

Name:	us-gaap_RegulatoryAssetsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant