Consolidated Balance Sheets (Parenthetical) - HECO (USD $)	Sep. 30, 2011	Dec. 31, 2010
Common stock, authorized shares	200,000,000	200,000,000
Common stock, outstanding shares	95,975,524	94,690,932
Hawaiian Electric Company, Inc. and Subsidiaries
Common stock, par value (in dollars per share)	$ 6.6667	$ 6.6667
Common stock, authorized shares	50,000,000	50,000,000
Common stock, outstanding shares	13,830,823	13,830,823