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Asset Retirement Obligations Asset Retirement Obligations (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2020 | Mar. 31, 2019
Asset Retirement Obligation Disclosure [Abstract] |  |
Assets recorded for asset retirement obligations | $ 69.8 | $ 4.8

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- References No definition available. + Details
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- Definition The increase (decrease) during the reporting period in the carrying amount of asset retirement obligations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 + Details
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