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Income taxes Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Changes in total unrecognized tax benefits |  |  |
Unrecognized tax benefits, at the beginning of the period | $ 0.9 | $ 0.8 | $ 5.7
Additions based on tax positions taken during the year | 0.0 | 0.0 | 0.3
Reductions based on tax positions taken during the year | 0.0 | 0.0 | 0.0
Additions for tax positions of prior years | 0.1 | 0.5 | 0.0
Reductions for tax positions of prior years | 0.0 | (0.4) | (4.1)
Settlements | (1.0) | 0.0 | 0.0
Lapses of statute of limitations | 0.0 | 0.0 | (1.1)
Unrecognized tax benefits, at the end of the period | 0.0 | 0.9 | 0.8
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |
Changes in total unrecognized tax benefits |  |  |
Unrecognized tax benefits, at the beginning of the period | 0.5 | 0.4 | 3.7
Additions based on tax positions taken during the year | 0.0 | 0.0 | 0.3
Reductions based on tax positions taken during the year | 0.0 | 0.0 | 0.0
Additions for tax positions of prior years | 0.1 | 0.5 | 0.0
Reductions for tax positions of prior years | 0.0 | (0.4) | (3.6)
Settlements | (0.6) | 0.0 | 0.0
Lapses of statute of limitations | 0.0 | 0.0 | 0.0
Unrecognized tax benefits, at the end of the period | $ 0.0 | $ 0.5 | $ 0.4

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- Definition Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Unrecognized Tax Benefit -URI http://asc.fasb.org/extlink&oid=6527854 + Details
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319 + Details
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