Electric utility segment (Details 5) (Hawaiian Electric Industries, Inc., HECO, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Hawaiian Electric Industries, Inc. | HECO
Related Party Transaction [Line Items]
Amount charged to subsidiaries for general management and administrative services	$ 6.2	$ 6.1	$ 4.9
Effective interest rate basis term	30 days
Line of credit facility basis point spread (as a percent)	0.15%