Fair value measurements (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Financial assets
Available-for-sale investment and mortgage-related securities	$ 711,347,000	$ 678,152,000
Financial liabilities
Short-term borrowings-other than bank		24,923,000
Other bank borrowings	239,122,000	237,319,000
American Savings Bank (ASB) \| Carrying or notional amount
Off-balance sheet items
Loan commitments and unused lines and letters of credit	1,300,000,000	1,200,000,000
Notional amount of loan serviced	849,000,000	818,000,000
Hawaiian Electric Company, Inc. and Subsidiaries \| Carrying or notional amount
Financial assets
Cash and cash equivalents, excluding money market accounts	844,000	122,936,000
Financial liabilities
Long-term debt, net-other than bank	1,058,006,000	1,057,942,000
Off-balance sheet items
HECO-obligated preferred securities of trust subsidiary	50,000,000	50,000,000
Carrying or notional amount
Financial assets
Cash and cash equivalents, excluding money market accounts	180,900,000	329,553,000
Money market accounts	85,846,000	1,098,000
Available-for-sale investment and mortgage-related securities	711,347,000	678,152,000
Investment in stock of Federal Home Loan Bank of Seattle	97,764,000	97,764,000
Loans receivable, net	3,585,202,000	3,497,729,000
Financial liabilities
Deposit liabilities	4,054,949,000	3,975,372,000
Short-term borrowings-other than bank		24,923,000
Other bank borrowings	239,122,000	237,319,000
Long-term debt, net-other than bank	1,440,006,000	1,364,942,000
Forward starting swaps		2,762,000
American Savings Bank (ASB) \| Estimated fair value
Off-balance sheet items
Loan commitments and unused lines and letters of credit	200,000	400,000
Servicing rights on loans	9,600,000	8,800,000
Hawaiian Electric Company, Inc. and Subsidiaries \| Estimated fair value
Financial assets
Cash and cash equivalents, excluding money market accounts	844,000	122,936,000
Financial liabilities
Long-term debt, net-other than bank	1,004,669,000	1,020,550,000
Off-balance sheet items
HECO-obligated preferred securities of trust subsidiary	50,040,000	52,500,000
Estimated fair value
Financial assets
Cash and cash equivalents, excluding money market accounts	180,900,000	329,553,000
Money market accounts	85,846,000	1,098,000
Available-for-sale investment and mortgage-related securities	711,347,000	678,152,000
Investment in stock of Federal Home Loan Bank of Seattle	97,764,000	97,764,000
Loans receivable, net	3,756,997,000	3,639,983,000
Financial liabilities
Deposit liabilities	4,058,762,000	3,979,027,000
Short-term borrowings-other than bank		24,923,000
Other bank borrowings	253,291,000	251,822,000
Long-term debt, net-other than bank	1,411,318,000	1,345,770,000
Forward starting swaps		$ 2,762,000

The fair value of financial commitments, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

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The carrying value of other bank borrowings as of the balance sheet date, including securities sold under agreements to repurchase and advances from the Federal Home Loan Bank.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

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-Publisher FASB
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Fair value as of the balance sheet date of all interest rate derivative liabilities designated as cash flow hedging instruments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Audit and Accounting Guide (AAG)
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-Paragraph 20
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-Topic 310
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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Paragraph 8, 9
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Sum of the carrying amounts at the balance sheet date of short-term borrowings not otherwise specified in the taxonomy having initial terms less than one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
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Fair value as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

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