Basis of presentation (Tables)

3 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Impact of Prior Period Financial Statements of the Adoption of ASU 2017-07

The following table summarizes the impact to the prior period financial statements of the adoption of ASU No. 2017-07:

(in thousands)	As previously filed			Adjustment from adoption of ASU No. 2017-07			As currently reported
Three months ended March 31, 2017
HEI Condensed Consolidated Income Statement
Expenses
Electric utility	$	469,673		$	(1,423	)	$	468,250
Bank	48,696			(195		)	48,501
Other	5,331			(258		)	5,073
Total expenses	523,700			(1,876		)	521,824
Operating income
Electric utility	48,938			1,423			50,361
Bank	24,160			195			24,355
Other	(5,236		)	258			(4,978		)
Total operating income	67,862			1,876			69,738
Retirement defined benefits expense--other than service costs	—			(1,876		)	(1,876		)
Hawaiian Electric Condensed Consolidated Income Statement
Other operation and maintenance	100,240			(1,423		)	98,817
Total expense	469,673			(1,423		)	468,250
Operating income	48,938			1,423			50,361
Retirement defined benefits expense--other than service costs	—			(1,423		)	(1,423		)
Hawaiian Electric Condensed Consolidating Income Statement (in Note 3)
Hawaiian Electric (parent only)
Other operation and maintenance	67,278			(1,285		)	65,993
Total expense	333,188			(1,285		)	331,903
Operating income	29,655			1,285			30,940
Retirement defined benefits expense--other than service costs	—			(1,285		)	(1,285		)
Hawaii Electric Light
Other operation and maintenance	15,516			83			15,599
Total expense	68,497			83			68,580
Operating income	10,485			(83		)	10,402
Retirement defined benefits expense--other than service costs	—			83			83
Maui Electric
Other operation and maintenance	17,446			(221		)	17,225
Total expense	67,988			(221		)	67,767
Operating income	8,805			221			9,026
Retirement defined benefits expense--other than service costs	—			(221		)	(221		)
ASB Statements of Income Data (in Note 4)
Compensation and employee benefits	23,237			(195		)	23,042
Other expense	4,311			195			4,506