Employee Benefit Plans (MEC) Narrative (Details) - MidAmerican Energy Company [Member] $ in Millions	6 Months Ended
Jun. 30, 2015 USD ($)
United States Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions in current fiscal year	$ 8
Employer contributions in current year	4
United States Defined Benefit Other Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions in current fiscal year	1
Employer contributions in current year	$ 0

The increase in the fair value of plan assets from contributions made by the employer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(3)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of the employer's best estimate of contributions expected to be paid to the plan in the current fiscal period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2709-114920

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