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v3.3.1.900

Commitments, Guarantees and Contingencies - Other Matters (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2015 USD ($) Years | Dec. 31, 2014
U.S. Water Services [Member] | Letters of Credit [Member] |  |
Guarantor Obligations [Line Items] |  |
Collateral | $ 0.8 |
BNI Energy Reclamation Liability [Member] |  |
Guarantor Obligations [Line Items] |  |
Estimated Obligation | 47.5 |
BNI Energy Reclamation Liability [Member] | Letters of Credit [Member] |  |
Guarantor Obligations [Line Items] |  |
Collateral | 0.6 |
BNI Energy Reclamation Liability [Member] | Surety Bonds [Member] |  |
Guarantor Obligations [Line Items] |  |
Collateral | 49.9 |
ALLETE Properties Development and Maintenance Obligations [Member] |  |
Guarantor Obligations [Line Items] |  |
Estimated Obligation | 6.3 |
ALLETE Properties Development and Maintenance Obligations [Member] | Surety Bonds and Letters of Credit [Member] |  |
Guarantor Obligations [Line Items] |  |
Collateral | 10.3 |
Town Center Community Development District Capital Improvement Bonds [Member] |  |
Guarantor Obligations [Line Items] |  |
Bonds | $ 26.4 |
Bond Interest Rate | 6.00% |
Bond Term (Years) | Years | 31 |
Ownership Percentage of Benefited Property | 72.00% | 72.00%
Annual Assessment | $ 1.4 |
Palm Coast Park Community Development District Special Assessment Bonds[Member] |  |
Guarantor Obligations [Line Items] |  |
Bonds | $ 31.8 |
Bond Interest Rate | 5.70% |
Bond Term (Years) | Years | 31 |
Ownership Percentage of Benefited Property | 89.00% | 93.00%
Annual Assessment | $ 2.1 |

X
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248 + Details
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