Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Renewal option range	10 years
Operating lease cost	$ 18,162
Variable lease cost	44,084
Total lease cost	62,246
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	$ 17,623
Weighted-average remaining lease term—operating leases (in years)	4 years
Weighted-average discount rate—operating leases	4.01%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 56,000
2020	73,000
2021	71,000
2022	47,000
2023	4,000
Thereafter	11,000
Total lease payments	262,000
Less: Imputed interest	(21,000)
Operating lease liabilities	241,340	$ 0
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	2,684
Variable lease cost	2,804
Total lease cost	5,488
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	$ 2,586
Weighted-average remaining lease term—operating leases (in years)	6 years 8 months 12 days
Weighted-average discount rate—operating leases	3.71%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 8,000
2020	10,000
2021	8,000
2022	5,000
2023	4,000
Thereafter	11,000
Total lease payments	46,000
Less: Imputed interest	(6,000)
Operating lease liabilities	40,000
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
Variable lease cost	41,280
Total lease cost	56,758
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	$ 15,037
Weighted-average remaining lease term—operating leases (in years)	3 years 6 months
Weighted-average discount rate—operating leases	4.08%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 48,000
2020	63,000
2021	63,000
2022	42,000
2023	0
Thereafter	0
Total lease payments	216,000
Less: Imputed interest	(15,000)
Operating lease liabilities	$ 201,000
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
Operating lease cost	$ 16,964
Variable lease cost	43,366
Total lease cost	60,330
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	$ 16,434
Weighted-average remaining lease term—operating leases (in years)	3 years 7 months 6 days
Weighted-average discount rate—operating leases	4.09%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 52,000
2020	69,000
2021	68,000
2022	44,000
2023	2,000
Thereafter	3,000
Total lease payments	238,000
Less: Imputed interest	(17,000)
Operating lease liabilities	221,000
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	1,486
Variable lease cost	2,086
Total lease cost	3,572
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	$ 1,397
Weighted-average remaining lease term—operating leases (in years)	5 years
Weighted-average discount rate—operating leases	4.17%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 4,000
2020	6,000
2021	5,000
2022	2,000
2023	2,000
Thereafter	3,000
Total lease payments	22,000
Less: Imputed interest	(2,000)
Operating lease liabilities	20,000
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
Variable lease cost	41,280
Total lease cost	56,758
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	$ 15,037
Weighted-average remaining lease term—operating leases (in years)	3 years 6 months
Weighted-average discount rate—operating leases	4.08%
Operating Lease Liabilities, Payments Due [Abstract]
2019	$ 48,000
2020	63,000
2021	63,000
2022	42,000
2023	0
Thereafter	0
Total lease payments	216,000
Less: Imputed interest	(15,000)
Operating lease liabilities	$ 201,000
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