Proposed Merger (Details)			1 Months Ended		4 Months Ended
	Aug. 07, 2015	Dec. 03, 2014 USD ($) $ / shares shares	Jul. 31, 2015 intervener	Jan. 31, 2015 USD ($)	Mar. 31, 2015 complaint	Apr. 30, 2015 action
Business Acquisition [Line Items]
Number of purported class action complaints filed | complaint					8
NextEra Energy, Inc Merger
Business Acquisition [Line Items]
Merger share conversion ratio | shares		0.2413
Minimum percentage of shares from which holders approval needed for merger		75.00%
Merger agreement contract extension		6 months
Merger contract termination fee | $		$ 90,000,000
Maximum expenses paid to party for cancellation of merger | $		$ 5,000,000
Minimum period that entity agrees not to submit applications for general base rate increase				4 years
Approximate amount of cumulative savings for customers due to forgone recoveries | $				$ 60,000,000
NextEra Energy, Inc Merger | Subsequent Event
Business Acquisition [Line Items]
Regulatory waiting period	30 days
Number of interveners			28
Number of interveners who opposed			11
Number of interveners opposed who approved conditionally			11
Number of interveners who made no recommendation			6
Hawaiian Electric Company, Inc. and Subsidiaries | NextEra Energy, Inc Merger
Business Acquisition [Line Items]
Special dividend | $ / shares		$ 0.50
In re Consolidated HEI Shareholder Cases
Business Acquisition [Line Items]
Consolidated number of state actions | action						7