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Discontinued operations Noncontrolling interest (Details) - USD ($) $ in Millions |  |  | 3 Months Ended
--- | --- | --- | ---
Jun. 27, 2016 | Jun. 24, 2016 | Mar. 31, 2017
WBI Energy | Dakota Prairie Refining, LLC |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Previous percentage of ownership | 50.00% | 50.00% |
Operating Expense | Refining |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Reversal of an accrual |  |  | $ 7.0
Operating expense - after tax | Refining |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |
Reversal of an accrual |  |  | $ 4.3

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