Represents the amount of fair value adjustments in loans held for sale.

No definition available.

Name:	he_LoansReceivableHeldForSaleAmountFairValueAdjustments
Namespace Prefix:	he_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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.

+ Details

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

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Definition

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5162-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4437-111522

+ Details

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

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=he_AmericanSavingsBankFSBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair value measurements - Assets Measured on a Nonrecurring Basis (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Estimated fair value
Fair value measurements on a recurring basis
Loans, net	$ 4,857,031,000	$ 4,802,053,000
Estimated fair value \| Level 1
Fair value measurements on a recurring basis
Loans, net	0	0
Estimated fair value \| Level 2
Fair value measurements on a recurring basis
Loans, net	8,146,000	1,809,000
Estimated fair value \| Level 3
Fair value measurements on a recurring basis
Loans, net	4,848,885,000	4,800,244,000
Fair value measurements on a nonrecurring basis \| American Savings Bank (ASB)
Fair value measurements on a recurring basis
Adjustments to fair value of loans held for sale	0		$ 0
Fair value measurements on a nonrecurring basis \| Level 1
Fair value measurements on a recurring basis
Loans, net	0	0
Real estate acquired in settlement of loans		0
Fair value measurements on a nonrecurring basis \| Level 2
Fair value measurements on a recurring basis
Loans, net	0	0
Real estate acquired in settlement of loans		0
Fair value measurements on a nonrecurring basis \| Level 3
Fair value measurements on a recurring basis
Loans, net	237,000	77,000
Real estate acquired in settlement of loans		186,000
Fair value measurements on a nonrecurring basis \| Estimated fair value
Fair value measurements on a recurring basis
Loans, net	$ 237,000	77,000
Real estate acquired in settlement of loans		$ 186,000