Long-term Debt (MEC) (Details) (MidAmerican Energy Company and Subsidiaries [Member], USD $)	12 Months Ended
Dec. 31, 2012
Debt Instrument [Line Items]
2013 long term debt maturities repayments	669,000,000
2014 long term debt maturities repayments	350,000,000
2015 long term debt maturities repayments	427,000,000
2016 long term debt maturities repayments	34,000,000
2017 long term debt maturities repayments	254,000,000
2018 and thereafter long term debt maturities repayments	1,557,000,000
Dividends available without affecting capital requirements	1,200,000,000
Committed Common Equity Percentage To Regulators [Member]
Debt Instrument [Line Items]
Common equity to total capitalization percentage	42.00%
Committed Common Equity Percentage To Regulators Beyond Companies Control [Member]
Debt Instrument [Line Items]
Common equity to total capitalization percentage below which reasonable efforts to maintain agreed to percentage is not required	39.00%
Common Equity Level To Total Capitalization [Member]
Debt Instrument [Line Items]
Common Equity Level To Total Capitalization	53.00%
MidAmerican Energy Company [Member] \| MEC Notes, 5.125% Series, due 2013 [Member]
Debt Instrument [Line Items]
Repurchased face amount	275,000,000
Interest rate	5.125%
Call premium on early redemption	8,000,000

The amount of call premium deferred as a regulatory asset due to early redemption.

No definition available.

Name:	mec_CallPremiumDeferredAsRegulatoryAsset
Namespace Prefix:	mec_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of common equity to total capitalization computed on a basis with its commitment to regulators.

+ References

No definition available.

+ Details

Name:	mec_CommonEquityLevelToTotalCapitalization
Namespace Prefix:	mec_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the minimum common equity to total capitalization percentage allowed under acquisition commitment without prior regulatory approval, unless there are circumstances beyond the entity’s control.

+ References

No definition available.

+ Details

Name:	mec_CommonEquityToTotalCapitalizationPercentage
Namespace Prefix:	mec_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

In the event there are circumstances beyond the entity’s control, represents the minimum common equity to total capitalization percentage allowed under acquisition commitment without prior regulatory approval.

+ References

No definition available.

+ Details

Name:	mec_CommonEquityToTotalCapitalizationPercentageBelowWhichReasonableEffortsToMaintainAgreedToPercentageIsNotRequired
Namespace Prefix:	mec_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of dividends that can be declared or paid without affecting the banking or savings institution's regulatory capital position.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(e))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph e

-Article 4

+ Details

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

- Definition

Interest rate stated in the contractual debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year.

+ References

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year.

+ References

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year.

+ References

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year.

+ References

+ Details

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

- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year.

+ References

+ Details

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