Leases (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Renewal option range	10 years	10 years
Operating lease cost	$ 18,534	$ 36,696
Variable lease cost	47,381	91,465
Total lease cost	65,915	128,161
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 16,922	$ 34,546
Weighted-average remaining lease term—operating leases (in years)	3 years 9 months 18 days	3 years 9 months 18 days
Weighted-average discount rate—operating leases	4.01%	4.01%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 37,000	$ 37,000
2020	73,000	73,000
2021	71,000	71,000
2022	47,000	47,000
2023	4,000	4,000
2024	3,000	3,000
Thereafter	8,000	8,000
Total lease payments	243,000	243,000
Less: Imputed interest	(17,000)	(17,000)
Operating lease liabilities	225,865	225,865
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			$ 74,000
2020			72,000
2021			71,000
2022			47,000
2023			4,000
Thereafter			12,000
Total lease payments			280,000
Other leases
Lessee, Lease, Description [Line Items]
Operating lease cost	3,056	5,740
Variable lease cost	3,396	6,200
Total lease cost	6,452	11,940
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 2,593	$ 5,179
Weighted-average remaining lease term—operating leases (in years)	6 years 7 months 6 days	6 years 7 months 6 days
Weighted-average discount rate—operating leases	3.70%	3.70%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 5,000	$ 5,000
2020	10,000	10,000
2021	8,000	8,000
2022	5,000	5,000
2023	4,000	4,000
2024	3,000	3,000
Thereafter	8,000	8,000
Total lease payments	43,000	43,000
Less: Imputed interest	(5,000)	(5,000)
Operating lease liabilities	38,000	38,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			11,000
2020			9,000
2021			8,000
2022			5,000
2023			4,000
Thereafter			12,000
Total lease payments			49,000
PPAs classified as leases
Lessee, Lease, Description [Line Items]
Operating lease cost	15,478	30,956
Variable lease cost	43,985	85,265
Total lease cost	59,463	116,221
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 14,329	$ 29,367
Weighted-average remaining lease term—operating leases (in years)	3 years 3 months 18 days	3 years 3 months 18 days
Weighted-average discount rate—operating leases	4.08%	4.08%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 32,000	$ 32,000
2020	63,000	63,000
2021	63,000	63,000
2022	42,000	42,000
2023	0	0
2024	0	0
Thereafter	0	0
Total lease payments	200,000	200,000
Less: Imputed interest	(12,000)	(12,000)
Operating lease liabilities	$ 188,000	$ 188,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			63,000
2020			63,000
2021			63,000
2022			42,000
2023			0
Thereafter			0
Total lease payments			231,000
Hawaiian Electric Company, Inc. and Subsidiaries
Lessee, Lease, Description [Line Items]
Renewal option range	10 years	10 years
Operating lease cost	$ 17,001	$ 33,965
Variable lease cost	46,749	90,115
Total lease cost	63,750	124,080
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 15,740	$ 32,175
Weighted-average remaining lease term—operating leases (in years)	3 years 4 months 24 days	3 years 4 months 24 days
Weighted-average discount rate—operating leases	4.09%	4.09%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 35,000	$ 35,000
2020	69,000	69,000
2021	68,000	68,000
2022	44,000	44,000
2023	2,000	2,000
2024	1,000	1,000
Thereafter	2,000	2,000
Total lease payments	221,000	221,000
Less: Imputed interest	(14,000)	(14,000)
Operating lease liabilities	207,000	207,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			69,000
2020			69,000
2021			68,000
2022			44,000
2023			2,000
Thereafter			3,000
Total lease payments			255,000
Hawaiian Electric Company, Inc. and Subsidiaries | Other leases
Lessee, Lease, Description [Line Items]
Operating lease cost	1,523	3,009
Variable lease cost	2,764	4,850
Total lease cost	4,287	7,859
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 1,411	$ 2,808
Weighted-average remaining lease term—operating leases (in years)	4 years 9 months 18 days	4 years 9 months 18 days
Weighted-average discount rate—operating leases	4.17%	4.17%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 3,000	$ 3,000
2020	6,000	6,000
2021	5,000	5,000
2022	2,000	2,000
2023	2,000	2,000
2024	1,000	1,000
Thereafter	2,000	2,000
Total lease payments	21,000	21,000
Less: Imputed interest	(2,000)	(2,000)
Operating lease liabilities	19,000	19,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			6,000
2020			6,000
2021			5,000
2022			2,000
2023			2,000
Thereafter			3,000
Total lease payments			24,000
Hawaiian Electric Company, Inc. and Subsidiaries | PPAs classified as leases
Lessee, Lease, Description [Line Items]
Operating lease cost	15,478	30,956
Variable lease cost	43,985	85,265
Total lease cost	59,463	116,221
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for amounts included in the measurement of lease liabilities—Operating cash flows from operating leases	$ 14,329	$ 29,367
Weighted-average remaining lease term—operating leases (in years)	3 years 3 months 18 days	3 years 3 months 18 days
Weighted-average discount rate—operating leases	4.08%	4.08%
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remaining months)	$ 32,000	$ 32,000
2020	63,000	63,000
2021	63,000	63,000
2022	42,000	42,000
2023	0	0
2024	0	0
Thereafter	0	0
Total lease payments	200,000	200,000
Less: Imputed interest	(12,000)	(12,000)
Operating lease liabilities	$ 188,000	$ 188,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019			63,000
2020			63,000
2021			63,000
2022			42,000
2023			0
Thereafter			0
Total lease payments			$ 231,000