Bank segment - Troubled debt restructuring - narrative (Details) $ in Millions	6 Months Ended
Jun. 30, 2016 USD ($)
Troubled debt restructurings real estate loans
Troubled debt restructurings
Financing receivable modifications minimum, period of payment default of loans determined to be TDRs	90 days
Commitments to lend additional funds to borrows with impaired or modified loans	$ 2.7
Land loans
Troubled debt restructurings
Period of interest-only monthly payment term loan	3 years
Land loans \| Maximum
Troubled debt restructurings
Extension of maturity date	5 years

Represents the extension of maturity period of troubled debt under the troubled debt restructuring plan.

No definition available.

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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

Represents the period of interest-only monthly payment term loan under the troubled debt restructuring plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	he_
Data Type:	xbrli:durationItemType
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Period Type:	duration

- 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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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Amount of restructured debt contingently payable based on the occurrence of future events or circumstances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 60
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6402221&loc=d3e15765-112638

+ Details

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- Details

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- Details

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- Details

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