Retirement benefits (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined contribution plan
Defined contribution plan, expenses recognized	$ 5,000,000	$ 4,000,000	$ 3,000,000
Cash contributions by the employer to defined contribution plan	4,000,000	4,000,000	4,000,000
Hawaiian Electric Industries, Inc.
Defined contribution plan
Maximum percentage of participant deferrals eligible for Employer contribution match, towards defined contribution plan	6.00%
Employer's additional matching contribution on employee deferrals (as a percent)	50.00%
Hawaiian Electric Company, Inc. and Subsidiaries
Defined contribution plan
Maximum percentage of participant deferrals eligible for Employer contribution match, towards defined contribution plan	6.00%
Employer's additional matching contribution on employee deferrals (as a percent)	50.00%
Defined contribution plan, expenses recognized	600,000
American Savings Bank (ASB)
Defined contribution plan
Maximum percentage of participant deferrals eligible for Employer contribution match, towards defined contribution plan	4.00%
Pension benefits
Defined benefit plans
Service cost	56,405,000	43,221,000	35,016,000
Interest cost	64,788,000	67,480,000	64,966,000
Expected return on plan assets	(72,537,000)	(71,183,000)	(68,901,000)
Amortization of net transition obligation	0	1,000	2,000
Amortization of net prior service gain	(97,000)	(325,000)	(389,000)
Amortization of net actuarial loss (gain)	38,438,000	25,675,000	16,987,000
Net periodic benefit cost	86,997,000	64,869,000	47,681,000
Impact of PUC D&Os	(38,104,000)	(15,754,000)	(3,516,000)
Net periodic benefit cost (adjusted for impact of PUC D&Os)	48,893,000	49,115,000	44,165,000
Amounts amortized from AOCI or regulatory assets into net periodic pension benefit cost during 2013
Prior service credit	100,000
Net actuarial loss	(20,200,000)
Net transition obligation	0
Pension expense	34,000,000	35,000,000	32,000,000
Pension benefits | Hawaiian Electric Company, Inc. and Subsidiaries
Defined benefit plans
Service cost	54,482,000	41,603,000	33,627,000
Interest cost	59,119,000	61,453,000	59,077,000
Expected return on plan assets	(64,551,000)	(64,004,000)	(61,615,000)
Amortization of net prior service gain	(464,000)	(689,000)	(747,000)
Amortization of net actuarial loss (gain)	34,597,000	23,428,000	15,752,000
Net periodic benefit cost	83,183,000	61,791,000	46,094,000
Impact of PUC D&Os	(38,104,000)	(15,754,000)	(3,516,000)
Net periodic benefit cost (adjusted for impact of PUC D&Os)	45,079,000	46,037,000	42,578,000
Amounts amortized from AOCI or regulatory assets into net periodic pension benefit cost during 2013
Prior service credit	100,000
Net actuarial loss	(18,200,000)
Net transition obligation	0
Pension expense	30,000,000	32,000,000	31,000,000
Other benefits
Defined benefit plans
Service cost	4,306,000	4,211,000	4,409,000
Interest cost	7,569,000	9,009,000	9,534,000
Expected return on plan assets	(10,147,000)	(10,336,000)	(10,650,000)
Amortization of net prior service gain	(1,793,000)	(1,793,000)	(1,494,000)
Amortization of net actuarial loss (gain)	1,602,000	1,498,000	234,000
Net periodic benefit cost	1,537,000	2,589,000	2,033,000
Impact of PUC D&Os	(1,458,000)	(2,227,000)	2,674,000
Net periodic benefit cost (adjusted for impact of PUC D&Os)	79,000	362,000	4,707,000
Amounts amortized from AOCI or regulatory assets into net periodic pension benefit cost during 2013
Prior service credit	(1,800,000)
Net actuarial loss	0
Net transition obligation	0
Postretirement benefits other than pension expense	400,000	1,000,000	4,000,000
Effect of one-percentage-point increase in assumed health care cost trend rates that would have increased total service and interest cost	300,000
Effect of one-percentage-point increase in assumed health care cost trend rates that would have increased the accumulated postretirement benefit obligation (APBO)	4,500,000
Effect of one-percentage-point decrease that would have reduced total service and interest cost	(300,000)
Effect of one-percentage-point decrease that would have reduced APBO	(4,900,000)
Other benefits | Hawaiian Electric Company, Inc. and Subsidiaries
Defined benefit plans
Service cost	4,163,000	4,014,000	4,238,000
Interest cost	7,288,000	8,703,000	9,228,000
Expected return on plan assets	(10,002,000)	(10,195,000)	(10,508,000)
Amortization of net transition obligation	0	(9,000)	(8,000)
Amortization of net prior service gain	(1,803,000)	(1,803,000)	(1,505,000)
Amortization of net actuarial loss (gain)	1,544,000	1,455,000	212,000
Net periodic benefit cost	1,190,000	2,165,000	1,657,000
Impact of PUC D&Os	(1,458,000)	(2,227,000)	2,674,000
Net periodic benefit cost (adjusted for impact of PUC D&Os)	(268,000)	(62,000)	4,331,000
Amounts amortized from AOCI or regulatory assets into net periodic pension benefit cost during 2013
Prior service credit	(1,800,000)
Net actuarial loss	0
Net transition obligation	0
Postretirement benefits other than pension expense	0	400,000	3,000,000
Effect of one-percentage-point increase in assumed health care cost trend rates that would have increased total service and interest cost	300,000
Effect of one-percentage-point increase in assumed health care cost trend rates that would have increased the accumulated postretirement benefit obligation (APBO)	4,500,000
Effect of one-percentage-point decrease that would have reduced total service and interest cost	(300,000)
Effect of one-percentage-point decrease that would have reduced APBO	$ (4,800,000)