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Termination of proposed merger and other matters (Details) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Jul. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Jun. 30, 2016 | Dec. 31, 2016
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Merger termination, expenses recognized |  |  | $ 1 | $ 1 |  |
NextEra Energy, Inc Merger |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Merger contract termination fee | $ 90 |  |  |  |  |
Maximum expenses paid to party for cancellation of merger | $ 5 |  |  |  |  |
Net income recognized on merger termination |  | $ 64 |  |  |  | $ 60
Gain (loss) recognized due to merger and spin-off related expenses, net of tax |  |  | $ (2) | $ (2) |  |
Net income recognized, merger termination fee |  | 55 |  |  |  |
Net income recognized, merger termination, reimbursements and insurance |  | $ 3 |  |  |  |
Recognition of previously disallowed merger expenses |  |  |  |  | $ 8 |
Net income recognized, merger and spin-off related expenses |  |  |  |  |  | $ 6

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- Definition Effective Income Tax Rate Reconciliation, Recognition Of Previously Disallowed Merger And Acquisition Expenses + References No definition available. + Details
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- Definition Gain (Loss) Recognized, Merger Termination + References No definition available. + Details
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- Definition Gain (Loss) Recognized, Merger Termination, Merger-and-spin-off Related Expenses + References No definition available. + Details
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- Definition Gain (Loss) Recognized, Merger Termination, Merger-and-spin-off Related Expenses, Net Of Taxes + References No definition available. + Details
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- Definition Gain (Loss) Recognized, Merger Termination, Reimbursements And Insurance + References No definition available. + Details
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- Definition Gain (Loss) Recognized, Merger Termination, Termination Fee + References No definition available. + Details
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- Definition Merger Termination, Expenses Recognized + References No definition available. + Details
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- Definition Proceeds from Merger Related Cost Reimbursement + References No definition available. + Details
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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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- Details
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- Details
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