Short-term borrowings (Details) (USD $)	12 Months Ended				0 Months Ended						12 Months Ended															0 Months Ended		0 Months Ended			0 Months Ended				0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 05, 2011 HEI Institution	Dec. 31, 2013 HEI	Dec. 31, 2012 HEI	Dec. 31, 2013 HEI Minimum	Dec. 05, 2011 HEI Minimum	Dec. 05, 2011 HEI Maximum	Dec. 31, 2013 Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2012 Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2011 Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 05, 2011 Hawaiian Electric Company, Inc. and Subsidiaries Institution	Dec. 31, 2010 Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 05, 2011 Hawaiian Electric Company, Inc. and Subsidiaries Maximum	Dec. 31, 2013 HELCO	Dec. 31, 2012 HELCO	Dec. 31, 2011 HELCO	Dec. 31, 2010 HELCO	Dec. 31, 2013 MECO	Dec. 31, 2012 MECO	Dec. 31, 2011 MECO	Dec. 31, 2010 MECO	Dec. 31, 2013 Interest rate on draws, alternative one	Dec. 05, 2011 Interest rate on draws, alternative one Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Interest rate on draws, alternative one Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 05, 2011 Interest rate on draws, alternative two HEI	Dec. 05, 2011 Interest rate on draws, alternative two Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Interest rate on draws, alternative three	Dec. 05, 2011 Interest rate on draws, alternative three HEI	Dec. 05, 2011 Interest rate on draws, alternative three Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Interest rate on draws, alternative three Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Interest rate on draws, alternative four	Dec. 05, 2011 Interest rate on draws, alternative four HEI	Dec. 05, 2011 Interest rate on draws, alternative four Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Interest rate on draws, alternative four Hawaiian Electric Company, Inc. and Subsidiaries	Dec. 31, 2013 Commercial paper HEI	Dec. 31, 2012 Commercial paper HEI
Short-term borrowings
Outstanding amount	$ 105,482,000	$ 83,693,000																																				$ 105,000,000	$ 84,000,000
Weighted-average interest rate (as a percent)																																						0.70%	0.90%
Maximum capacity under syndicated credit facilities					125,000,000						175,000,000			175,000,000
Credit agreements
Maximum capacity under syndicated credit facilities					125,000,000						175,000,000			175,000,000
Number of financial institutions					8									8
Line of credit facility, reference rate					Adjusted LIBO Rate																					Adjusted LIBO Rate		Prime Rate	Prime Rate		Federal Funds Rate	Federal Funds Rate			“Adjusted LIBO Rate” for a one month “Interest Period”	“Adjusted LIBO Rate” for a one month “Interest Period”
Line of credit facility basis point spread (as a percent)																									1.50%		1.50%			0.50%			0.50%	0.50%			0.50%
Annual fees on undrawn commitments, basis points (as a percent)	0.25%										0.25%
Capitalization ratio required to be maintained as per the debt covenant (as a percent)										50.00%
Actual capitalization ratio (as a percent)						18.00%
Consolidated net worth	1,727,070,000	1,593,865,000	1,528,706,000	1,480,394,000		1,727,070,000	1,593,865,000		975,000,000		1,593,564,000	1,472,136,000	1,402,841,000		1,334,155,000		274,802,000	268,908,000	280,468,000	269,986,000	248,771,000	228,927,000	235,568,000	229,651,000
Consolidated net worth calculated under the agreement								$ 1,800,000,000
Ratio of consolidated subsidiary debt to total consolidated capitalization required to be maintained as per the debt covenant (as a percent)																65.00%
Actual ratio of consolidated subsidiary debt to total consolidated capitalization (as a percent)																	42.00%				43.00%
Ratio of consolidated capitalization required to be maintained as per the debt covenant (as a percent)																35.00%
Actual ratio of consolidated debt to total consolidated capitalization (as a percent)											56.00%