Commitments and Contingencies Commitments and Contingencies - MEC- Commitments (Details) - MidAmerican Energy Company [Member] $ in Millions	Sep. 30, 2018 USD ($)
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Operating Leases, Future Minimum Payments Due	$ 422
Capital Addition Purchase Commitments [Member]
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Purchase Obligation	563
Maintenance, service and other contracts [Member]
ContractualObligationFiscalYearMaturityScheduleTable [Line Items]
Purchase Obligation	$ 226

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 3)
-URI http://asc.fasb.org/extlink&oid=82846649&loc=d3e38371-112697

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902758&loc=d3e41502-112717

Name:	us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant