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Related Party Transactions - Related Party Transactions included in Consolidated Income Statement (Details) - USD ($) $ in Millions | 9 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  |  | $ 0 | $ 0
Interest expense to affiliates, net |  |  | $ 25 | 36 | 41
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | (28) | (32) | (24)
Equity in earnings (losses) of unconsolidated affiliates |  |  | (28) | (32) | (24)
Cash dividends paid to parent |  |  | 1,332 | 1,236 | 1,166
Corporate, Non-Segment [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | (1) | 7 | 10
Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [1] |  | (2) | 0 |
PECO Energy Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [1] |  | 0 | 1 | 1
Baltimore Gas And Electric Company Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [1] |  | 0 | 4 | 4
Atlantic City Electric Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [1] |  | 0 | 0 | 0
ComEd Financing III Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 13 | 14 | 13
PECO Trust III Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 6 | 6 | 6
PECO Trust IV Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 6 | 6 | 6
BGE Capital Trust II Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 0 | 10 | 16
Qualifying Facilities And Domestic Power Projects Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | (29) | (33) | (25)
Other Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 2 | 5
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | 1 | 1 | 1
Exelon Generation Co L L C [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1,268 | 1,115 | 1,439
Related Party Transaction, Purchases from Related Party |  |  | 14 | 19 | 12
Operating and maintenance from affiliates |  |  | 661 | 697 | 663
Interest expense to affiliates, net |  |  | 36 | 39 | 39
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | (30) | (33) | (25)
Equity in earnings (losses) of unconsolidated affiliates |  |  | (30) | (33) | (25)
Cash distribution paid to member |  |  | 1,001 | 659 | 922
Cash contributions received from affiliates |  |  | 155 | 102 | 142
Exelon Generation Co L L C [Member] | Commonwealth Edison Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [2] |  | 523 | 121 | 47
Related Party Transaction, Purchases from Related Party |  |  | (6) | 13 | 0
Operating and maintenance from affiliates | [3] |  | 7 | 7 | 7
Exelon Generation Co L L C [Member] | PECO Energy Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [4] |  | 128 | 138 | 290
Operating and maintenance from affiliates | [3] |  | 2 | 1 | 3
Interest expense to affiliates, net |  |  | 0 | 1 | 0
Exelon Generation Co L L C [Member] | Baltimore Gas And Electric Company Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [5] |  | 260 | 388 | 608
Related Party Transaction, Purchases from Related Party |  |  | 20 | 9 | 12
Operating and maintenance from affiliates | [3] |  | 2 | 1 | 1
Exelon Generation Co L L C [Member] | Potomac Electric Power Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [6] |  | 206 | 255 | 295
Operating and maintenance from affiliates |  |  | 1 | 0 | 1
Exelon Generation Co L L C [Member] | Delmarva Power & Light Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [7] |  | 120 | 179 | 154
Exelon Generation Co L L C [Member] | Atlantic City Electric Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [8] |  | 29 | 29 | 37
Exelon Generation Co L L C [Member] | PHI Service Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance from affiliates |  |  | 1 | 1 | 1
Exelon Generation Co L L C [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net | [9] |  | 36 | 37 | 39
Cash distribution paid to member |  |  | 1,001 | 659 | 922
Cash contributions received from affiliates |  |  | 155 | 102 | 142
Exelon Generation Co L L C [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 2 | 1 | 2
Operating and maintenance from affiliates | [10] |  | 652 | 689 | 650
Capitalized costs | [10] |  | 67 | 98 | 98
Exelon Generation Co L L C [Member] | Potomac Capital Investment Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 0 | 1 | 0
Exelon Generation Co L L C [Member] | Qualifying Facilities And Domestic Power Projects Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | (30) | (33) | (25)
Exelon Generation Co L L C [Member] | Other Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 0 | 4 | 6
Related Party Transaction, Purchases from Related Party |  |  | 0 | (3) | 0
Operating and maintenance from affiliates |  |  | (4) | (2) | 0
Commonwealth Edison Co [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 27 | 15 | 15
Related Party Transaction, Purchases from Related Party |  |  | 529 | 108 | 47
Operating and maintenance from affiliates |  |  | 267 | 270 | 227
Interest expense to affiliates, net |  |  | 13 | 13 | 13
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 459 | 422 | 369
Proceeds from Contributions from Parent |  |  | 500 | 651 | 315
Commonwealth Edison Co [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 9 | 9 | 7
Related Party Transaction, Purchases from Related Party | [11] |  | 529 | 108 | 47
Commonwealth Edison Co [Member] | PECO Energy Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 10 | 0 | 1
Operating and maintenance from affiliates |  |  | 1 | 0 | 1
Commonwealth Edison Co [Member] | Baltimore Gas And Electric Company Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 1
Operating and maintenance from affiliates |  |  | 1 | 0 | 1
Commonwealth Edison Co [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  |  | 459 | 422 | 369
Proceeds from Contributions from Parent |  |  | 500 | 651 | 315
Commonwealth Edison Co [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 7 | 6 | 6
Operating and maintenance from affiliates | [12] |  | 265 | 270 | 225
Capitalized costs | [12] |  | 135 | 118 | 112
Commonwealth Edison Co [Member] | ComEd Financing III Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 13 | 13 | 13
PECO Energy Co [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 8 | 7 | 8
Related Party Transaction, Purchases from Related Party |  |  | 126 | 135 | 287
Operating and maintenance from affiliates |  |  | 156 | 149 | 146
Interest expense to affiliates, net |  |  | 14 | 11 | 12
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 306 | 288 | 277
Proceeds from Contributions from Parent |  |  | 89 | 16 | 18
PECO Energy Co [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [13] |  | 2 | 1 | 3
Related Party Transaction, Purchases from Related Party | [14] |  | 126 | 135 | 287
Operating and maintenance from affiliates |  |  | 2 | 2 | 2
Interest income from affiliates, net |  |  | 0 | (1) | 0
PECO Energy Co [Member] | Commonwealth Edison Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 1
Operating and maintenance from affiliates |  |  | 7 | 0 | 1
PECO Energy Co [Member] | Baltimore Gas And Electric Company Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 1 | 1
Operating and maintenance from affiliates |  |  | 1 | 1 | 1
PECO Energy Co [Member] | Atlantic City Electric Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 0
PECO Energy Co [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 2 | 0 | 0
Cash dividends paid to parent |  |  | 306 | 288 | 277
Proceeds from Contributions from Parent |  |  | 89 | 16 | 18
PECO Energy Co [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 3 | 5 | 3
Operating and maintenance from affiliates | [15] |  | 146 | 146 | 142
Capitalized costs | [15] |  | 64 | 59 | 57
PECO Energy Co [Member] | PECO Trust III Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 6 | 6 | 6
PECO Energy Co [Member] | PECO Trust IV Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 6 | 6 | 6
Baltimore Gas and Electric Company [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 29 | 16 | 21
Related Party Transaction, Purchases from Related Party |  |  | 257 | 384 | 604
Operating and maintenance from affiliates |  |  | 162 | 153 | 132
Interest expense to affiliates, net |  |  | 0 | 10 | 16
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 209 | 198 | 179
Proceeds from Contributions from Parent |  |  | 109 | 184 | 61
Baltimore Gas and Electric Company [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [16] |  | 22 | 10 | 13
Related Party Transaction, Purchases from Related Party | [17] |  | 257 | 384 | 604
Operating and maintenance from affiliates |  |  | 3 | 0 | 0
Baltimore Gas and Electric Company [Member] | Commonwealth Edison Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 1
Operating and maintenance from affiliates |  |  | 1 | 0 | 1
Baltimore Gas and Electric Company [Member] | PECO Energy Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 1 | 1
Operating and maintenance from affiliates |  |  | 1 | 1 | 1
Baltimore Gas and Electric Company [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  |  | 209 | 198 | 179
Proceeds from Contributions from Parent |  |  | 109 | 184 | 61
Baltimore Gas and Electric Company [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 5 | 5 | 6
Operating and maintenance from affiliates | [18] |  | 157 | 152 | 130
Capitalized costs | [18] |  | 79 | 54 | 36
Baltimore Gas and Electric Company [Member] | BGE Capital Trust II Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Interest expense to affiliates, net |  |  | 0 | 10 | 16
Pepco Holdings LLC [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 15 | 50 |
Related Party Transaction, Purchases from Related Party |  |  | 355 | 463 |
Operating and maintenance from affiliates |  |  | 152 | 150 |
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  |  | 1 | 1 |
Equity in earnings (losses) of unconsolidated affiliates |  |  | 1 | 1 |
Cash distribution paid to member |  |  | 326 | 311 |
Proceeds from Contributions from Parent |  |  | 385 | 758 |
Pepco Holdings LLC [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  | $ 45 | 15 | 50 |
Related Party Transaction, Purchases from Related Party |  | 486 |  |  |
Operating and maintenance from affiliates |  | 89 | 152 | 150 |
Capitalized costs |  | 0 | 181 | 0 |
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  | 0 |  |  |
Equity in earnings (losses) of unconsolidated affiliates |  | 0 |  |  |
Cash distribution paid to member |  | 273 |  |  |
Proceeds from Contributions from Parent |  | 1,251 |  |  |
Pepco Holdings LLC [Member] | Exelon Generation Co LLC Affiliate [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  | 1 | 2 | 0 |
Related Party Transaction, Purchases from Related Party |  | 486 | 355 | 463 |
Pepco Holdings LLC [Member] | PHI Service Co Affiliate [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  | 0 | 1 | 2 |
Capitalized costs | [19] | 0 | 79 | 0 |
Pepco Holdings LLC [Member] | Exelon Corporation Affiliate [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  | 1,251 | 326 | 311 |
Proceeds from Contributions from Parent |  | 273 | 385 | 758 |
Pepco Holdings LLC [Member] | Exelon Business Services Co Affiliate [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  | 44 | 12 | 48 |
Operating and maintenance from affiliates | [19] | 86 | 147 | 145 |
Capitalized costs | [19] | 0 | 102 | 0 |
Pepco Holdings LLC [Member] | Other Affiliate [Member] | Successor [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance from affiliates |  | 3 | 5 | 5 |
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |  | $ 0 | 1 | 0 |
Potomac Electric Power Company [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 6 | 6 | 5
Related Party Transaction, Purchases from Related Party |  |  | 206 | 255 | 295
Operating and maintenance from affiliates |  |  | 226 | 58 | 35
Capitalized costs |  |  | 72 | 0 | 0
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 169 | 133 | 136
Proceeds from Contributions from Parent |  |  | 166 | 161 | 187
Potomac Electric Power Company [Member] | Corporate, Non-Segment [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance |  |  | 0 | 248 | 302
Potomac Electric Power Company [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates | [20] |  | 1 | 0 | 1
Related Party Transaction, Purchases from Related Party | [21] |  | 206 | 255 | 295
Potomac Electric Power Company [Member] | PHI Service Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 4 | 6 | 4
Operating and maintenance from affiliates | [22],[23] |  | 137 | 5 | 4
Operating and maintenance | [22],[23] |  | 0 | 219 | 263
Capitalized costs | [23] |  | 32 | 0 | 0
Potomac Electric Power Company [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  |  | 169 | 133 | 136
Proceeds from Contributions from Parent |  |  | 166 | 161 | 187
Potomac Electric Power Company [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 0
Operating and maintenance from affiliates | [23] |  | 89 | 53 | 31
Capitalized costs | [23] |  | 40 | 0 | 0
Potomac Electric Power Company [Member] | Pepco Energy Services Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance | [24] |  | 0 | 29 | 39
Delmarva Power & Light Company [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 8 | 8 | 7
Related Party Transaction, Purchases from Related Party |  |  | 120 | 179 | 154
Operating and maintenance from affiliates |  |  | 162 | 32 | 19
Capitalized costs |  |  | 53 | 0 | 0
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 96 | 112 | 54
Proceeds from Contributions from Parent |  |  | 150 | 0 | 152
Delmarva Power & Light Company [Member] | Corporate, Non-Segment [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance |  |  | 0 | 174 | 202
Delmarva Power & Light Company [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Related Party Transaction, Purchases from Related Party | [25] |  | 120 | 179 | 154
Delmarva Power & Light Company [Member] | Commonwealth Edison Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 0
Delmarva Power & Light Company [Member] | Atlantic City Electric Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 0
Delmarva Power & Light Company [Member] | PHI Service Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 4 | 6 | 5
Operating and maintenance from affiliates | [26],[27] |  | 111 | 0 | 0
Operating and maintenance | [26],[27] |  | 0 | 165 | 194
Capitalized costs | [26] |  | 25 | 0 | 0
Delmarva Power & Light Company [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  |  | 96 | 112 | 54
Proceeds from Contributions from Parent |  |  | 150 | 0 | 152
Delmarva Power & Light Company [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 0 | 0
Operating and maintenance from affiliates | [26] |  | 51 | 31 | 18
Capitalized costs | [26] |  | 28 | 0 | 0
Delmarva Power & Light Company [Member] | Pepco Energy Services Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance | [28] |  | 0 | 9 | 8
Delmarva Power & Light Company [Member] | Other Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 2 | 2
Operating and maintenance from affiliates |  |  | 0 | 1 | 1
Atlantic City Electric Company [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 3 | 2 | 3
Related Party Transaction, Purchases from Related Party |  |  | 29 | 29 | 37
Operating and maintenance from affiliates |  |  | 142 | 28 | 18
Capitalized costs |  |  | 41 | 0 | 0
Equity in earnings (losses) of unconsolidated affiliates |  |  | 0 | 0 | 0
Cash dividends paid to parent |  |  | 59 | 68 | 63
Proceeds from Contributions from Parent |  |  | 67 | 0 | 139
Atlantic City Electric Company [Member] | Exelon Generation Co LLC Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Related Party Transaction, Purchases from Related Party | [29] |  | 29 | 29 | 37
Atlantic City Electric Company [Member] | PHI Service Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 2 | 1 | 2
Operating and maintenance from affiliates | [30],[31] |  | 98 | 0 | 0
Operating and maintenance | [30],[31] |  | 0 | 135 | 155
Capitalized costs | [30] |  | 21 | 0 | 0
Atlantic City Electric Company [Member] | Exelon Corporation Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Cash dividends paid to parent |  |  | 59 | 68 | 63
Cash contributions received from affiliates |  |  | 67 | 0 | 139
Atlantic City Electric Company [Member] | Exelon Business Services Co Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating and maintenance from affiliates | [30] |  | 42 | 25 | 15
Capitalized costs | [30] |  | 20 | 0 | 0
Atlantic City Electric Company [Member] | Other Affiliate [Member] |  |  |  |  |
Related Party Transaction [Line Items] |  |  |  |  |
Operating revenues from affiliates |  |  | 1 | 1 | 1
Operating and maintenance from affiliates |  |  | $ 2 | $ 3 | $ 3
[1] | The intersegment profit associated with the sale of certain products and services by and between Exelon’s segments is not eliminated in consolidation due to the recognition of intersegment profit in accordance with regulatory authoritative guidance. For Exelon, these amounts are included in operating revenues in the Consolidated Statements of Operations. See Note 4—Regulatory Matters for additional information.
[2] | Generation has an ICC-approved RFP contract with ComEd to provide a portion of ComEd’s electricity supply requirements. Generation also sells RECs and ZECs to ComEd.
[3] | Generation requires electricity for its own use at its generating stations. Generation purchases electricity and distribution and transmission services from PECO and BGE and only distribution and transmission services from ComEd for the delivery of electricity to its generating stations.
[4] | Generation provides electric supply to PECO under contracts executed through PECO’s competitive procurement process. In addition, Generation has a ten-year agreement with PECO to sell solar AECs.
[5] | Generation provides a portion of BGE’s energy requirements under its MDPSC-approved market-based SOS and gas commodity programs.
[6] | Generation provides electric supply to Pepco under contracts executed through Pepco's competitive procurement process approved by the MDPSC and DCPSC.
[7] | Generation provides a portion of DPL's energy requirements under its MDPSC and DPSC approved market based SOS and gas commodity programs.
[8] | Generation provides electric supply to ACE under contracts executed through ACE's competitive procurement process.
[9] | The balance consists of interest owed to Exelon Corporation related to the senior unsecured notes, as well as, expense related to certain invoices Exelon Corporation processed on behalf of Generation.
[10] | Generation receives a variety of corporate support services from BSC and PHISCO, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[11] | ComEd procures a portion of its electricity supply requirements from Generation under an ICC-approved RFP contract. ComEd also purchases RECs and ZECs from Generation.
[12] | ComEd receives a variety of corporate support services from BSC, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[13] | PECO provides energy to Generation for Generation’s own use.
[14] | PECO purchases electric supply from Generation under contracts executed through its competitive procurement process. In addition, PECO has five-year and ten-year agreements with Generation to purchase non-solar and solar AECs, respectively.
[15] | PECO receives a variety of corporate support services from BSC, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[16] | BGE provides energy to Generation for Generation’s own use.
[17] | BGE procures a portion of its electricity and gas supply requirements from Generation under its MDPSC-approved market-based SOS and gas commodity programs.
[18] | BGE receives a variety of corporate support services from BSC, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[19] | PHI receives a variety of corporate support services from BSC and PHISCO, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[20] | Pepco provides energy to Generation for Generation’s own use.
[21] | Pepco procures a portion of its electricity supply requirements from Generation under its MDPSC and DCPSC approved market based SOS commodity programs.
[22] | Due to the PHI entities' system conversion to Exelon's accounting systems on January 1, 2018, corporate support services received from PHISCO are reported in Operating and maintenance from affiliates in 2018.
[23] | Pepco receives a variety of corporate support services from BSC and PHISCO, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[24] | PES performed underground transmission, distribution construction and maintenance services, including services that are treated as capital costs, for Pepco.
[25] | DPL procures a portion of its electricity and gas supply requirements from Generation under its MDPSC and DPSC approved market based SOS and gas commodity programs.
[26] | DPL receives a variety of corporate support services from BSC and PHISCO, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[27] | Due to the PHI entities' system conversion to Exelon's accounting systems on January 1, 2018, corporate support services received from PHISCO are reported in Operating and maintenance from affiliates in 2018.
[28] | PES performed underground transmission construction services, including services that are treated as capital costs, for DPL.
[29] | ACE purchases electric supply from Generation under contracts executed through its competitive procurement process.
[30] | ACE receives a variety of corporate support services from BSC and PHISCO, including legal, human resources, financial, information technology and supply management services. All services are provided at cost, including applicable overhead. A portion of such services is capitalized.
[31] | Due to the PHI entities' system conversion to Exelon's accounting systems on January 1, 2018, corporate support services received from PHISCO are reported in Operating and maintenance from affiliates in 2018.

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