Income taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The Company’s ETRs (combined federal and state income tax rates) for the second quarters of 2017 and 2016 were 34% and 37%, respectively, and for the first six months of 2017 and 2016 were 34% and 37%, respectively. The ETR was lower for the three months and six months ended June 30, 2017 compared to the same periods in 2016 due in part to 2016 nondeductible merger- and spin-off-related expenses. Also, in the first quarter of 2017, the Company recognized excess tax benefits on share-based compensation after the adoption of ASU No. 2016-09. Hawaiian Electric’s ETRs for the second quarters of 2017 and 2016 were 36% and 38%, respectively, and for the first six months of 2017 and 2016 were 36% and 37%, respectively. The lower ETR was due in part to the recognition of excess tax benefits on share-based compensation after the adoption of ASU No. 2016-09. Recent tax developments. The extension of bonus depreciation under the “Protecting Americans from Tax Hikes (PATH) Act of 2015” continues to be the most significant recent tax change. The PATH Act provides 50% bonus depreciation through 2017, phases down the percentage to 40% in 2018 and 30% in 2019 and then terminates bonus depreciation thereafter. Tax depreciation is expected to increase by approximately $120 million in 2017 due to bonus depreciation, which has the effect of increasing accumulated deferred tax liabilities. However, the rate of growth of accumulated deferred tax liabilities is decreasing over time as book depreciation “catches up” with the tax depreciation taken in the past.

Income taxes

6 Months Ended

Jun. 30, 2017

The Company’s ETRs (combined federal and state income tax rates) for the second quarters of 2017 and 2016 were 34% and 37%, respectively, and for the first six months of 2017 and 2016 were 34% and 37%, respectively. The ETR was lower for the three months and six months ended June 30, 2017 compared to the same periods in 2016 due in part to 2016 nondeductible merger- and spin-off-related expenses. Also, in the first quarter of 2017, the Company recognized excess tax benefits on share-based compensation after the adoption of ASU No. 2016-09.

Hawaiian Electric’s ETRs for the second quarters of 2017 and 2016 were 36% and 38%, respectively, and for the first six months of 2017 and 2016 were 36% and 37%, respectively. The lower ETR was due in part to the recognition of excess tax benefits on share-based compensation after the adoption of ASU No. 2016-09.

Recent tax developments. The extension of bonus depreciation under the “Protecting Americans from Tax Hikes (PATH) Act of 2015” continues to be the most significant recent tax change. The PATH Act provides 50% bonus depreciation through 2017, phases down the percentage to 40% in 2018 and 30% in 2019 and then terminates bonus depreciation thereafter. Tax depreciation is expected to increase by approximately $120 million in 2017 due to bonus depreciation, which has the effect of increasing accumulated deferred tax liabilities. However, the rate of growth of accumulated deferred tax liabilities is decreasing over time as book depreciation “catches up” with the tax depreciation taken in the past.