Proposed Merger (Details) (USD $)	4 Months Ended	0 Months Ended	1 Months Ended
	Mar. 31, 2015 complaint	Dec. 03, 2014	Jan. 31, 2015	Apr. 30, 2015 action
Business Acquisition [Line Items]
Number of purported class action complaints filed	8
NextEra Energy, Inc Merger
Business Acquisition [Line Items]
Merger share conversion ratio		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
Hawaiian Electric Company, Inc. and Subsidiaries | NextEra Energy, Inc Merger
Business Acquisition [Line Items]
Special dividend		$ 0.50
In re Consolidated HEI Shareholder Cases | Subsequent Event
Business Acquisition [Line Items]
Consolidated number of state actions				7