Bank segment (HEI only) - Capital And Ratio (Details) - American Savings Bank (ASB) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 leverage, actual capital	$ 571,810	$ 542,239
Tier 1 leverage, actual ratio	8.58%	8.59%
Tier 1 leverage, required capital	$ 266,430	$ 252,515
Tier 1 leverage, required ratio	4.00%	4.00%
Tier 1 leverage, required to be well capitalized capital	$ 333,038	$ 315,644
Tier 1 leverage, required to be well capitalized ratio	5.00%	5.00%
Common equity tier 1, actual capital	$ 571,810	$ 542,239
Common equity tier 1, actual ratio	12.95%	12.17%
Common equity tier 1, required capital	$ 198,628	$ 200,455
Common equity tier 1, required ratio	4.50%	4.50%
Common equity tier 1, required to be well capitalized, Capital	$ 286,907	$ 289,545
Common equity tier 1, required to be well capitalized, Ratio	6.50%	6.50%
Tier 1 capital, actual capital	$ 571,810	$ 542,239
Tier 1 capital, actual ratio	12.95%	12.17%
Tier 1 capital, required capital	$ 264,838	$ 267,273
Tier 1 capital, required ratio	6.00%	6.00%
Tier 1 capital, Required to be well capitalized, Capital	$ 353,117	$ 356,364
Tier 1 capital, Required to be well capitalized, Ratio	8.00%	8.00%
Total capital, Actual capital	$ 626,987	$ 597,940
Total capital, Actual ratio	14.20%	13.42%
Total capital, Required capital	$ 353,117	$ 356,364
Total capital, Required ratio	8.00%	8.00%
Total capital, Required to be well capitalized, Capital	$ 441,396	$ 445,455
Total capital, Required to be well capitalized, Ratio	10.00%	10.00%

Common Equity Tier One Capital

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Common Equity Tier One Capital Required For Capital Adequacy

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Common Equity Tier One Capital Required To Be Well Capitalized

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Common Equity Tier One Required To Be Well Caplitalized To Risk Weighted Assets

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Common Equity Tier One Required for Capital Adequacy to Average Assets

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Common Equity Tier One To Average Assets

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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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.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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