Represents the number of entities involved in the business of segment.

No definition available.

Name:	he_NumberOfEntitiesInvolvedInSegment
Namespace Prefix:	he_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Balance represents total tangible assets.

+ References

No definition available.

+ Details

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

- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

Name:	us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

Name:	us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ 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.(h))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Income Tax Expense (or Benefit)

-URI http://asc.fasb.org/extlink&oid=6515339

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a),(b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

+ Details

Name:	us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.9)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 9

-Article 9

+ Details

Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256

+ Details

Name:	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after tax of income (loss) attributable to redeemable noncontrolling preferred unit holders.

+ References

+ Details

Name:	us-gaap_NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4K

-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

-Paragraph 19

-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4J

-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686

+ Details

Name:	us-gaap_ProfitLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_IntersegmentEliminationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

Segment financial information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment financial information
Revenues	$ 790,040us-gaap_Revenues	$ 867,096us-gaap_Revenues	$ 798,657us-gaap_Revenues	$ 783,749us-gaap_Revenues	$ 832,503us-gaap_Revenues	$ 829,168us-gaap_Revenues	$ 794,567us-gaap_Revenues	$ 782,232us-gaap_Revenues	$ 3,239,542us-gaap_Revenues	$ 3,238,470us-gaap_Revenues	$ 3,374,995us-gaap_Revenues
Depreciation and amortization									181,238	164,728	158,347
Interest expense									87,160us-gaap_InterestExpense	85,556us-gaap_InterestExpense	89,443us-gaap_InterestExpense
Income (loss) before income taxes									261,922	247,747	217,407
Income taxes (benefit)									91,712us-gaap_IncomeTaxExpenseBenefit	84,341us-gaap_IncomeTaxExpenseBenefit	76,859us-gaap_IncomeTaxExpenseBenefit
Net income	33,630us-gaap_ProfitLoss	48,286us-gaap_ProfitLoss	41,894us-gaap_ProfitLoss	46,400us-gaap_ProfitLoss	39,486us-gaap_ProfitLoss	48,707us-gaap_ProfitLoss	41,061us-gaap_ProfitLoss	34,152us-gaap_ProfitLoss	170,210us-gaap_ProfitLoss	163,406us-gaap_ProfitLoss	140,548us-gaap_ProfitLoss
Preferred stock dividends of subsidiaries									1,890	1,890	1,890
Net income for common stock	33,157	47,815	41,421	45,927	39,013	48,236	40,588	33,679	168,320	161,516	138,658
Capital expenditures									339,721	353,879	325,480
Assets	11,184,161he_TangibleAssets				10,340,044he_TangibleAssets				11,184,161he_TangibleAssets	10,340,044he_TangibleAssets	10,149,132he_TangibleAssets
Electric utility
Segment financial information
Number of entities involved									3
Revenues									2,987,323	2,980,172	3,109,439
Depreciation and amortization									174,478	159,102	151,496
Interest expense									64,757	59,279	62,055
Income (loss) before income taxes									220,361	194,041	162,319
Income taxes (benefit)									80,725	69,117	61,048
Net income									139,636	124,924	101,271
Preferred stock dividends of subsidiaries									1,995	1,995	1,995
Net income for common stock									137,641	122,929	99,276
Capital expenditures									311,574	342,485	310,091
Assets	5,590,457				5,087,129				5,590,457	5,087,129	5,108,793
Bank
Segment financial information
Revenues									252,497	258,147	265,539
Depreciation and amortization									5,399	4,230	5,334
Interest expense									10,808	10,077	11,292
Income (loss) before income taxes									75,619	87,059	89,021
Income taxes (benefit)									24,127	29,525	30,384
Net income									51,492	57,534	58,637
Preferred stock dividends of subsidiaries									0	0	0
Net income for common stock									51,492	57,534	58,637
Capital expenditures									28,073	11,193	14,979
Assets	5,565,241				5,243,824				5,565,241	5,243,824	5,041,673
Other
Segment financial information
Revenues									(278)	151	17
Depreciation and amortization									1,361	1,396	1,517
Interest expense									11,595	16,200	16,096
Income (loss) before income taxes									(34,058)	(33,353)	(33,933)
Income taxes (benefit)									(13,140)	(14,301)	(14,573)
Net income									(20,918)	(19,052)	(19,360)
Preferred stock dividends of subsidiaries									(105)	(105)	(105)
Net income for common stock									(20,813)	(18,947)	(19,255)
Capital expenditures									74	201	410
Assets	28,463				9,091				28,463	9,091	(1,334)
Operating Segments
Segment financial information
Revenues									3,239,542	3,238,470	3,374,995
Operating Segments \| Electric utility
Segment financial information
Revenues									2,987,299	2,980,139	3,109,353
Operating Segments \| Bank
Segment financial information
Revenues									252,497	258,147	265,539
Operating Segments \| Other
Segment financial information
Revenues									(254)	184	103
Intersegment eliminations
Segment financial information
Revenues									0	0	0
Intersegment eliminations \| Electric utility
Segment financial information
Revenues									24	33	86
Intersegment eliminations \| Bank
Segment financial information
Revenues									0	0	0
Intersegment eliminations \| Other
Segment financial information
Revenues									$ (24)	$ (33)	$ (86)