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Electric utility segment - Annual decoupling filings summary (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2017 USD ($)
Hawaiian Electric (parent only) |
Regulatory Projects and Legal Obligations [Line Items] |
2018 Annual incremental RAM adjusted revenues | $ 13.8
Annual change in accrued RBA balance as of December 31, 2017 (and associated revenue taxes) | 6.6
2017 Tax Act Adjustment | 0.0
Net annual incremental amount to be collected under the tariffs | 20.4
HELCO |
Regulatory Projects and Legal Obligations [Line Items] |
2018 Annual incremental RAM adjusted revenues | 3.4
Annual change in accrued RBA balance as of December 31, 2017 (and associated revenue taxes) | 0.7
2017 Tax Act Adjustment | 0.0
Net annual incremental amount to be collected under the tariffs | 4.1
Maui Electric |
Regulatory Projects and Legal Obligations [Line Items] |
2018 Annual incremental RAM adjusted revenues | 2.0
Annual change in accrued RBA balance as of December 31, 2017 (and associated revenue taxes) | 3.2
2017 Tax Act Adjustment | (2.8)
Net annual incremental amount to be collected under the tariffs | $ 2.4

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