Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionExercisableNumber
Namespace Prefix:	he_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) during the reporting period.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExercisesInPeriodIntrinsicValue
Namespace Prefix:	he_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The decrease in the number of shares that could be issued attributable to the lapse of rights to exercise previously issued awards other than stock options under the terms of the award agreements under the plan during the reporting period.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpirationsInPeriod
Namespace Prefix:	he_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Disclosure of the aggregate tax benefit realized from the exercise of stocks and the conversion of similar instruments during the annual period.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTaxBenefitRealizedFromExerciseOfStocks
Namespace Prefix:	he_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionExercisesInPeriodWeightedAverageExercisePrice
Namespace Prefix:	he_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the plan.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisableWeightedAverageExercisePrice
Namespace Prefix:	he_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements other than options exercisable and outstanding.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExercisePriceRangeExercisableWeightedAverageExercisePrice
Namespace Prefix:	he_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

The weighted average price at which grantees could have exercised with respect to awards that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsExpiredInPeriodWeightedAverageExercisePrice
Namespace Prefix:	he_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The number of shares under the Stock Appreciation Rights plan that validly exist and are outstanding and exercisable for which the share appreciation payment is calculated upon exercise.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsOutstandingAndExercisableNumber
Namespace Prefix:	he_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The weighted average period between the balance sheet date and expiration for all awards outstanding and exercisable under the plan, which may be expressed in a decimal value for number of years.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsOutstandingAndExercisableWeightedAverageRemainingContractualTerm
Namespace Prefix:	he_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The weighted average price as of the end of the period at which grantees can acquire the shares reserved for issuance under the award plan.

No definition available.

Name:	he_ShareBasedCompensationArrangementByShareBasedPaymentAwardOtherThanOptionsOutstandingWeightedAverageExercisePrice
Namespace Prefix:	he_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Share-based Compensation, Stock Appreciation Rights [Roll Forward]

No definition available.

Name:	he_SharebasedCompensationStockAppreciationRightsRollForward
Namespace Prefix:	he_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of shares other than options (or share units) exercised during the current period.

No definition available.

Name:	he_StockIssuedDuringPeriodSharesAwardOtherThanOptionsExercised
Namespace Prefix:	he_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(3)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901