Electric utility subsidiary - Consolidating financial statements (Details 5) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities
Net income	$ 46,400,000	$ 34,152,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation of property, plant and equipment	43,181,000	39,726,000
Other amortization	1,609,000	935,000
Increase in deferred income taxes	6,298,000	19,967,000
Allowance for equity funds used during construction	(1,609,000)	(1,215,000)
Change in cash overdraft	(1,038,000)	0
Changes in assets and liabilities
Decrease (increase) in fuel oil stock	(34,260,000)	(29,272,000)
Increase in regulatory assets	(9,258,000)	(17,746,000)
Decrease in prepaid and accrued income and utility revenue taxes	(19,474,000)	(50,933,000)
Decrease in defined benefit pension and other postretirement benefit plans liability	(818,000)	(702,000)
Net cash provided by operating activities	19,421,000	48,319,000
Cash flows from investing activities
Capital expenditures	(65,829,000)	(71,041,000)
Contributions in aid of construction	6,958,000	11,710,000
Net cash used in investing activities	(74,232,000)	(112,551,000)
Cash flows from financing activities
Common stock dividends	(31,435,000)	(24,394,000)
Net increase in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	30,887,000	50,244,000
Other	(3,953,000)	(3,240,000)
Net cash provided by financing activities	103,895,000	107,278,000
Net increase (decrease) in cash and cash equivalents	49,084,000	43,046,000
Hawaiian Electric Company
Cash flows from operating activities
Net income	35,690,000	24,699,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	(8,942,000)	(11,010,000)
Common stock dividends received from subsidiaries	6,595,000	7,052,000
Depreciation of property, plant and equipment	27,301,000	24,707,000
Other amortization	235,000	(8,000)
Increase in deferred income taxes	17,123,000	13,572,000
Change in tax credits, net	1,741,000	1,299,000
Allowance for equity funds used during construction	(1,472,000)	(983,000)
Changes in assets and liabilities
Decrease in accounts receivable	4,131,000	34,652,000
Decrease (increase) in accrued unbilled revenues	11,031,000	(1,707,000)
Decrease (increase) in fuel oil stock	(35,060,000)	(30,155,000)
Increase in materials and supplies	(330,000)	(1,853,000)
Increase in regulatory assets	(8,188,000)	(13,071,000)
Increase (decrease) in accounts payable	(837,000)	44,887,000
Decrease in prepaid and accrued income and utility revenue taxes	(39,581,000)	(41,093,000)
Decrease in defined benefit pension and other postretirement benefit plans liability	(103,000)	0
Change in other assets and liabilities	(10,874,000)	(4,413,000)
Net cash provided by operating activities	(1,540,000)	46,575,000
Cash flows from investing activities
Capital expenditures	(49,432,000)	(47,709,000)
Contributions in aid of construction	4,541,000	7,816,000
Advances from (to) affiliates	(12,661,000)	(3,600,000)
Net cash used in investing activities	(57,552,000)	(43,493,000)
Cash flows from financing activities
Common stock dividends	(22,707,000)	(20,070,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(270,000)	(270,000)
Net increase in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	34,096,000	41,652,000
Other	(320,000)	2,000
Net cash provided by financing activities	10,799,000	21,314,000
Net increase (decrease) in cash and cash equivalents	(48,293,000)	24,396,000
Cash and cash equivalents, beginning of period	61,245,000	8,265,000
Cash and cash equivalents, end of period	12,952,000	32,661,000
HELCO
Cash flows from operating activities
Net income	5,295,000	4,554,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation of property, plant and equipment	8,975,000	8,547,000
Other amortization	501,000	358,000
Increase in deferred income taxes	862,000	2,755,000
Change in tax credits, net	217,000	(17,000)
Allowance for equity funds used during construction	(65,000)	(138,000)
Changes in assets and liabilities
Decrease in accounts receivable	2,029,000	(13,000)
Decrease (increase) in accrued unbilled revenues	(230,000)	(2,091,000)
Decrease (increase) in fuel oil stock	1,166,000	2,056,000
Increase in materials and supplies	(387,000)	(614,000)
Increase in regulatory assets	(881,000)	(2,464,000)
Increase (decrease) in accounts payable	(6,032,000)	(903,000)
Decrease in prepaid and accrued income and utility revenue taxes	(2,791,000)	(8,078,000)
Decrease in defined benefit pension and other postretirement benefit plans liability	0	(57,000)
Change in other assets and liabilities	1,041,000	2,464,000
Net cash provided by operating activities	9,700,000	6,359,000
Cash flows from investing activities
Capital expenditures	(7,530,000)	(10,118,000)
Contributions in aid of construction	1,121,000	3,432,000
Advances from (to) affiliates	900,000	1,400,000
Net cash used in investing activities	(5,509,000)	(5,286,000)
Cash flows from financing activities
Common stock dividends	(2,941,000)	(3,610,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(134,000)	(134,000)
Other	0	0
Net cash provided by financing activities	(3,075,000)	(3,744,000)
Net increase (decrease) in cash and cash equivalents	1,116,000	(2,671,000)
Cash and cash equivalents, beginning of period	1,326,000	5,441,000
Cash and cash equivalents, end of period	2,442,000	2,770,000
Maui Electric
Cash flows from operating activities
Net income	3,851,000	6,660,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation of property, plant and equipment	5,327,000	5,026,000
Other amortization	885,000	607,000
Increase in deferred income taxes	2,359,000	1,648,000
Change in tax credits, net	74,000	100,000
Allowance for equity funds used during construction	(72,000)	(94,000)
Change in cash overdraft	(1,038,000)
Changes in assets and liabilities
Decrease in accounts receivable	2,194,000	3,495,000
Decrease (increase) in accrued unbilled revenues	1,459,000	2,481,000
Decrease (increase) in fuel oil stock	(366,000)	(1,173,000)
Increase in materials and supplies	(328,000)	(878,000)
Increase in regulatory assets	(189,000)	(2,211,000)
Increase (decrease) in accounts payable	(9,155,000)	(5,050,000)
Decrease in prepaid and accrued income and utility revenue taxes	(5,154,000)	(4,495,000)
Decrease in defined benefit pension and other postretirement benefit plans liability	(102,000)	10,000
Change in other assets and liabilities	(698,000)	1,493,000
Net cash provided by operating activities	(953,000)	7,619,000
Cash flows from investing activities
Capital expenditures	(7,500,000)	(10,088,000)
Contributions in aid of construction	1,296,000	462,000
Net cash used in investing activities	(6,204,000)	(9,626,000)
Cash flows from financing activities
Common stock dividends	(3,629,000)	(3,442,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(95,000)	(95,000)
Net increase in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	12,661,000	3,600,000
Other	(69,000)	0
Net cash provided by financing activities	8,868,000	63,000
Net increase (decrease) in cash and cash equivalents	1,711,000	(1,944,000)
Cash and cash equivalents, beginning of period	153,000	3,349,000
Cash and cash equivalents, end of period	1,864,000	1,405,000
Other subsidiaries
Cash flows from operating activities
Net income	0	0
Changes in assets and liabilities
Net cash provided by operating activities	0	0
Cash flows from financing activities
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	101,000	104,000
Cash and cash equivalents, end of period	101,000	104,000
Consolidating adjustments
Cash flows from operating activities
Net income	(8,917,000)	(10,985,000)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	8,917,000	10,985,000
Common stock dividends received from subsidiaries	(6,570,000)	(7,052,000)
Changes in assets and liabilities
Decrease in accounts receivable	450,000	569,000
Change in other assets and liabilities	(450,000)	(569,000)
Net cash provided by operating activities	(6,570,000)	(7,052,000)
Cash flows from investing activities
Advances from (to) affiliates	11,761,000	2,200,000
Net cash used in investing activities	11,761,000	2,200,000
Cash flows from financing activities
Common stock dividends	6,570,000	7,052,000
Net increase in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(11,761,000)	(2,200,000)
Net cash provided by financing activities	(5,191,000)	4,852,000
HECO Consolidated
Cash flows from operating activities
Net income	35,919,000	24,928,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	(25,000)	(25,000)
Common stock dividends received from subsidiaries	25,000	0
Depreciation of property, plant and equipment	41,603,000	38,280,000
Other amortization	1,621,000	957,000
Increase in deferred income taxes	20,344,000	17,975,000
Change in tax credits, net	2,032,000	1,382,000
Allowance for equity funds used during construction	(1,609,000)	(1,215,000)
Change in cash overdraft	(1,038,000)	0
Changes in assets and liabilities
Decrease in accounts receivable	8,804,000	38,703,000
Decrease (increase) in accrued unbilled revenues	12,260,000	(1,317,000)
Decrease (increase) in fuel oil stock	(34,260,000)	(29,272,000)
Increase in materials and supplies	(1,045,000)	(3,345,000)
Increase in regulatory assets	(9,258,000)	(17,746,000)
Increase (decrease) in accounts payable	(16,024,000)	38,934,000
Decrease in prepaid and accrued income and utility revenue taxes	(47,526,000)	(53,666,000)
Decrease in defined benefit pension and other postretirement benefit plans liability	(205,000)	(47,000)
Change in other assets and liabilities	(10,981,000)	(1,025,000)
Net cash provided by operating activities	637,000	53,501,000
Cash flows from investing activities
Capital expenditures	(64,462,000)	(67,915,000)
Contributions in aid of construction	6,958,000	11,710,000
Net cash used in investing activities	(57,504,000)	(56,205,000)
Cash flows from financing activities
Common stock dividends	(22,707,000)	(20,070,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(499,000)	(499,000)
Net increase in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	34,996,000	43,052,000
Other	(389,000)	2,000
Net cash provided by financing activities	11,401,000	22,485,000
Net increase (decrease) in cash and cash equivalents	(45,466,000)	19,781,000
Cash and cash equivalents, beginning of period	62,825,000	17,159,000
Cash and cash equivalents, end of period	$ 17,359,000	$ 36,940,000