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Mergers, Acquisitions and Dispositions Merger Commitments Table (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Mar. 31, 2017
--- | --- | ---
Other Commitments [Line Items] |  |
Other Commitment | $ 127 |
Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment |  | $ 444
Exelon Consolidations [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 508 |
Exelon Consolidations [Member] | Rate Bill Credits [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 259 |
Exelon Consolidations [Member] | Energy Efficiency Program [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 117 |
Exelon Consolidations [Member] | Charitable Contributions [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 50 |
Exelon Consolidations [Member] | Delivery System Modernization [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 22 |
Exelon Consolidations [Member] | Green Sustainability Fund [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 14 |
Exelon Consolidations [Member] | Workforce Development [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 17 |
Exelon Consolidations [Member] | Other1 [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 29 |
Exelon Consolidations [Member] | Remaining Commitment [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 128 |
Atlantic City Electric Company [Member] | Remaining Commitment [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 7 |
Delmarva Power & Light Company [Member] | Remaining Commitment [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 12 |
Potomac Electric Power Company [Member] | Remaining Commitment [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 73 |
Pepco Holdings LLC [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 320 |
Pepco Holdings LLC [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 120 |
Pepco Holdings LLC [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 89 |
Pepco Holdings LLC [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 111 |
Pepco Holdings LLC [Member] | Rate Bill Credits [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 264 |
Pepco Holdings LLC [Member] | Rate Bill Credits [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 91 |
Pepco Holdings LLC [Member] | Rate Bill Credits [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 72 |
Pepco Holdings LLC [Member] | Rate Bill Credits [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 101 |
Pepco Holdings LLC [Member] | Energy Efficiency Program [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Energy Efficiency Program [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Energy Efficiency Program [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Energy Efficiency Program [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Charitable Contributions [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 50 |
Pepco Holdings LLC [Member] | Charitable Contributions [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 28 |
Pepco Holdings LLC [Member] | Charitable Contributions [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 12 |
Pepco Holdings LLC [Member] | Charitable Contributions [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 10 |
Pepco Holdings LLC [Member] | Delivery System Modernization [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Delivery System Modernization [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Delivery System Modernization [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Delivery System Modernization [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Green Sustainability Fund [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Green Sustainability Fund [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Green Sustainability Fund [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Green Sustainability Fund [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Workforce Development [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Workforce Development [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Workforce Development [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Workforce Development [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Other1 [Member] | Pepco Holdings LLC [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 6 |
Pepco Holdings LLC [Member] | Other1 [Member] | Potomac Electric Power Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 1 |
Pepco Holdings LLC [Member] | Other1 [Member] | Delmarva Power & Light Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 5 |
Pepco Holdings LLC [Member] | Other1 [Member] | Atlantic City Electric Company [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | 0 |
Pepco Holdings LLC [Member] | Remaining Commitment [Member] |  |
Other Commitments [Line Items] |  |
Other Commitment | $ 92 |

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