Retirement benefits (Details 2) - HECO (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Reclassifications out of accumulated other comprehensive income/(loss)
Amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost	$ (5,789)	$ (3,826)	$ (17,490)	$ (11,467)
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets	5,156	3,342	15,468	10,026
Amount reclassified from AOCI
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	692	543	1,461	1,537
Retirement benefit plan items | Amount reclassified from AOCI
Reclassifications out of accumulated other comprehensive income/(loss)
Amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost	5,789	3,826	17,490	11,467
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets	(5,156)	(3,342)	(15,468)	(10,026)
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassifications out of accumulated other comprehensive income/(loss)
Amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost	(5,173)	(3,419)	(15,520)	(10,255)
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets	5,156	3,342	15,468	10,026
Hawaiian Electric Company, Inc. and Subsidiaries | Retirement benefit plan items | Amount reclassified from AOCI
Reclassifications out of accumulated other comprehensive income/(loss)
Amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost	5,173	3,419	15,520	10,255
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets	(5,156)	(3,342)	(15,468)	(10,026)
Total reclassifications	$ 17	$ 77	$ 52	$ 229