Consolidated Balance Sheets (Parenthetical) - HECO (USD $)	Mar. 31, 2013	Dec. 31, 2012
Common stock, authorized shares	200,000,000	200,000,000
Common stock, outstanding shares	98,471,405	97,928,403
Hawaiian Electric Company, Inc. and Subsidiaries
Common stock, par value (in dollars per share)	6.67	6.67
Common stock, authorized shares	50,000,000	50,000,000
Common stock, outstanding shares	14,665,264	14,665,264