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Fair Value Measurements - Concentration of Credit Risk (Details) $ in Millions | Mar. 31, 2018 USD ($)
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Two largest counterparties | Concentration of Credit Risk | Credit Exposure |
Concentration Risk [Line Items] |
Total credit risk | $ 28.1

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- Definition Maximum potential amount of future undiscounted payments that could be required under the credit derivative, 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 815 -SubTopic 10 -Section 50 -Paragraph 4K -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5708775-113959 + Details
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