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Consolidated Balance Sheets (Parenthetical) - shares shares in Millions | Mar. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Limited Partners Common Units | Public |  |
Units issued | 289 | 289
Units outstanding | 289 | 289
Limited Partners Common Units | MPC |  |
Units issued | 505 | 118
Units outstanding | 505 | 118
General Partner | MPC |  |
GP units issued | 0 | 8
GP units outstanding | 0 | 8

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