Bank segment (HEI only) - Loan Modifications (Details)	12 Months Ended
Dec. 31, 2018 USD ($) contract	Dec. 31, 2017 USD ($) contract	Dec. 31, 2016 USD ($) contract
Loan modifications determined to be troubled debt restructurings
Commitments to borrowers whose loan terms are impaired or modified under troubled debt restructuring	$ 0	$ 0
Troubled debt restructurings real estate loans
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	81	64	67
Pre-modification outstanding recorded investment	$ 12,920,000	$ 4,798,000	$ 26,937,000
Post-modification outstanding recorded investment	12,961,000	4,792,000	27,052,000
Net increase in ALLL	$ 1,413,000	$ 877,000	$ 1,756,000
Minimum period of payment default of loans determined to be TDRs	90 days	90 days	90 days
Troubled debt restructurings real estate loans \| Residential 1-4 family
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	5	7	14
Pre-modification outstanding recorded investment	$ 1,107,000	$ 742,000	$ 3,131,000
Post-modification outstanding recorded investment	1,133,000	750,000	3,245,000
Net increase in ALLL	$ 17,000	$ 45,000	$ 337,000
Troubled debt restructurings real estate loans \| Commercial real estate
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	0	0	0
Net increase in ALLL	$ 0	$ 0	$ 0
Troubled debt restructurings real estate loans \| Home equity line of credit
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	58	46	36
Pre-modification outstanding recorded investment	$ 7,487,000	$ 3,016,000	$ 3,337,000
Post-modification outstanding recorded investment	7,492,000	3,002,000	3,337,000
Net increase in ALLL	$ 1,220,000	$ 557,000	$ 554,000
Troubled debt restructurings real estate loans \| Residential land
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	5	1	2
Pre-modification outstanding recorded investment	$ 1,776,000	$ 92,000	$ 203,000
Post-modification outstanding recorded investment	1,786,000	92,000	204,000
Net increase in ALLL	$ 0	$ 0	$ 0
Troubled debt restructurings real estate loans \| Commercial construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	0	0	0
Net increase in ALLL	$ 0	$ 0	$ 0
Troubled debt restructurings real estate loans \| Residential construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Pre-modification outstanding recorded investment	$ 0	$ 0	$ 0
Post-modification outstanding recorded investment	0	0	0
Net increase in ALLL	$ 0	$ 0	$ 0
Troubled debt restructurings real estate loans \| Commercial
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	13	9	15
Pre-modification outstanding recorded investment	$ 2,550,000	$ 889,000	$ 20,266,000
Post-modification outstanding recorded investment	2,550,000	889,000	20,266,000
Net increase in ALLL	$ 176,000	$ 248,000	$ 865,000
Troubled debt restructurings real estate loans \| Consumer
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	1	0
Pre-modification outstanding recorded investment	$ 0	$ 59,000	$ 0
Post-modification outstanding recorded investment	0	59,000	0
Net increase in ALLL	$ 0	$ 27,000	$ 0
Troubled debt restructurings that subsequently defaulted
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	2	1	2
Recorded investment	$ 327,000	$ 222,000	$ 263,000
Consumer mortgage loans collateralized by residential real estate property in foreclosure process	$ 4,200,000	$ 4,300,000
Troubled debt restructurings that subsequently defaulted \| Residential 1-4 family
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	1	1
Recorded investment	$ 0	$ 222,000	$ 239,000
Troubled debt restructurings that subsequently defaulted \| Commercial real estate
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Recorded investment	$ 0	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted \| Home equity line of credit
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	1	0	0
Recorded investment	$ 81,000	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted \| Residential land
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Recorded investment	$ 0	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted \| Commercial construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Recorded investment	$ 0	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted \| Residential construction
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Recorded investment	$ 0	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted \| Commercial
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	1	0	1
Recorded investment	$ 246,000	$ 0	$ 24,000
Troubled debt restructurings that subsequently defaulted \| Consumer
Loan modifications determined to be troubled debt restructurings
Number of contracts \| contract	0	0	0
Recorded investment	$ 0	$ 0	$ 0

Represents the commitments to borrowers whose loan terms are impaired or modified under troubled debt restructuring.

No definition available.

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Namespace Prefix:	he_
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- Definition

Financial Receivables, Loans Collateralized by Real Estate in Foreclosure

+ References

No definition available.

+ Details

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- Definition

Represents the minimum period of payment default of loans determined to be troubled debt restructurings.

+ References

No definition available.

+ Details

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- Definition

The number of contracts under financing receivables that have been modified by troubled debt restructurings during the period.

+ References

No definition available.

+ Details

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- Definition

The amount of the outstanding recorded investment in financial receivables after the financial receivables being modified as troubled debt restructurings.

+ References

No definition available.

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- Definition

The amount of the outstanding recorded investment in financial receivables prior to the financial receivables being modified as troubled debt restructurings.

+ References

No definition available.

+ Details

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- Definition

Amount of increase (decrease) of allowance reserve for credit loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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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.

+ Details

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

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