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Property, Plant and Equipment Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Millions | 9 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 99,609 | $ 95,266 |
Less: accumulated depreciation | [1] |  | 22,902 | 21,064 |
Property, plant and equipment, net |  |  | 76,707 | 74,202 |
Impairment of Long-Lived Assets Held-for-use |  |  | 50 | 573 | $ 306
Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 53,090 | 49,506 |
Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 90 years |  |
Electric—generation |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 29,170 | 29,019 |
Electric—generation | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Electric—generation | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 56 years |  |
Gas Distribution Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 5,530 | 5,050 |
Gas Distribution Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Gas Distribution Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 90 years |  |
Common—electric and gas |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 1,627 | 1,447 |
Common—electric and gas | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Common—electric and gas | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Nuclear Fuel [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [2] |  | $ 5,957 | 6,420 |
Nuclear Fuel [Member] | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Nuclear Fuel [Member] | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 8 years |  |
Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 3,377 | 2,825 |
Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [3] |  | $ 858 | 999 |
Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 50 years |  |
Exelon Generation Co L L C [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 36,187 | 36,334 |
Less: accumulated depreciation | [4] |  | 12,206 | 11,428 |
Property, plant and equipment, net |  |  | 23,981 | 24,906 |
Nuclear fuel - work in progress |  |  | 1,004 | 1,196 |
Capital Leases, Balance Sheet, Assets by Major Class, Net |  |  | 5 | 7 |
Capital Leased Assets, Gross |  |  | 47 | 47 |
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation |  |  | 42 | 40 |
Impairment of Long-Lived Assets Held-for-use |  |  | 50 | 510 | 243
Exelon Generation Co L L C [Member] | Electric—generation |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 29,170 | 29,019 |
Exelon Generation Co L L C [Member] | Electric—generation | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Exelon Generation Co L L C [Member] | Electric—generation | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 56 years |  |
Exelon Generation Co L L C [Member] | Nuclear Fuel [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [5] |  | $ 5,957 | 6,420 |
Less: accumulated depreciation |  |  | $ 2,969 | 3,159 |
Exelon Generation Co L L C [Member] | Nuclear Fuel [Member] | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Exelon Generation Co L L C [Member] | Nuclear Fuel [Member] | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 8 years |  |
Exelon Generation Co L L C [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 997 | 838 |
Exelon Generation Co L L C [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [6] |  | $ 63 | 57 |
Exelon Generation Co L L C [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 1 year |  |
Exelon Generation Co L L C [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 8 years |  |
Commonwealth Edison Co [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 26,742 | 24,992 |
Less: accumulated depreciation |  |  | 4,684 | 4,269 |
Property, plant and equipment, net |  |  | 22,058 | 20,723 |
Capital Leases, Balance Sheet, Assets by Major Class, Net |  |  | 7 | 7 |
Capital Leased Assets, Gross |  |  | 8 | 8 |
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation |  |  | 1 | 1 |
Plant Held for Future Use Amount |  |  | 39 |  |
Commonwealth Edison Co [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 25,991 | 24,423 |
Commonwealth Edison Co [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Commonwealth Edison Co [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 80 years |  |
Commonwealth Edison Co [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 705 | 517 |
Commonwealth Edison Co [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [7],[8] |  | $ 46 | 52 |
Commonwealth Edison Co [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 35 years |  |
Commonwealth Edison Co [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 50 years |  |
PECO Energy Co [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 12,171 | 11,464 |
Less: accumulated depreciation |  |  | 3,561 | 3,411 |
Property, plant and equipment, net |  |  | 8,610 | 8,053 |
Plant Held for Future Use Amount |  |  | 19 |  |
PECO Energy Co [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 8,359 | 7,975 |
PECO Energy Co [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
PECO Energy Co [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 65 years |  |
PECO Energy Co [Member] | Gas Distribution Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 2,694 | 2,504 |
PECO Energy Co [Member] | Gas Distribution Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
PECO Energy Co [Member] | Gas Distribution Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 70 years |  |
PECO Energy Co [Member] | Common—electric and gas |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 756 | 710 |
PECO Energy Co [Member] | Common—electric and gas | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
PECO Energy Co [Member] | Common—electric and gas | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 50 years |  |
PECO Energy Co [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 343 | 254 |
PECO Energy Co [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [9] |  | $ 19 | 21 |
Average Service Life (years) |  |  | 50 years |  |
Baltimore Gas and Electric Company [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 11,876 | 11,007 |
Less: accumulated depreciation |  |  | 3,633 | 3,405 |
Property, plant and equipment, net |  |  | 8,243 | 7,602 |
Plant Held for Future Use Amount |  |  | 25 |  |
Impairment of Long-Lived Assets Held-for-use |  |  | 0 | 7 | 52
Baltimore Gas and Electric Company [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 7,951 | 7,464 |
Baltimore Gas and Electric Company [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Baltimore Gas and Electric Company [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 90 years |  |
Baltimore Gas and Electric Company [Member] | Gas Distribution Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 2,630 | 2,379 |
Baltimore Gas and Electric Company [Member] | Gas Distribution Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Baltimore Gas and Electric Company [Member] | Gas Distribution Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 90 years |  |
Baltimore Gas and Electric Company [Member] | Common—electric and gas |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 860 | 771 |
Baltimore Gas and Electric Company [Member] | Common—electric and gas | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Baltimore Gas and Electric Company [Member] | Common—electric and gas | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 40 years |  |
Baltimore Gas and Electric Company [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 410 | 367 |
Baltimore Gas and Electric Company [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [10] |  | $ 25 | 26 |
Average Service Life (years) |  |  | 20 years |  |
Pepco Holdings LLC [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 14,287 | 12,985 |
Less: accumulated depreciation |  |  | 841 | 487 |
Property, plant and equipment, net |  |  | 13,446 | 12,498 |
Impairment of Long-Lived Assets Held-for-use |  |  | 0 | 52 |
Pepco Holdings LLC [Member] | Successor [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Impairment of Long-Lived Assets Held-for-use |  | $ 0 |  |  |
Pepco Holdings LLC [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 12,664 | 11,517 |
Pepco Holdings LLC [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Pepco Holdings LLC [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Pepco Holdings LLC [Member] | Gas Distribution Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 486 | 449 |
Pepco Holdings LLC [Member] | Gas Distribution Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Pepco Holdings LLC [Member] | Gas Distribution Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Pepco Holdings LLC [Member] | Common—electric and gas |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 126 | 82 |
Pepco Holdings LLC [Member] | Common—electric and gas | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Pepco Holdings LLC [Member] | Common—electric and gas | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Pepco Holdings LLC [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 912 | 835 |
Pepco Holdings LLC [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [11] |  | $ 99 | 102 |
Pepco Holdings LLC [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 3 years |  |
Pepco Holdings LLC [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 43 years |  |
Potomac Electric Power Company [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 9,814 | 9,178 |
Less: accumulated depreciation |  |  | 3,354 | 3,177 |
Property, plant and equipment, net |  |  | 6,460 | 6,001 |
Plant Held for Future Use Amount |  |  | 61 |  |
Impairment of Long-Lived Assets Held-for-use |  |  | 0 | 14 | 0
Potomac Electric Power Company [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 9,217 | 8,646 |
Potomac Electric Power Company [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Potomac Electric Power Company [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Potomac Electric Power Company [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 536 | 473 |
Potomac Electric Power Company [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [12] |  | $ 61 | 59 |
Potomac Electric Power Company [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 25 years |  |
Potomac Electric Power Company [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 33 years |  |
Delmarva Power & Light Company [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 5,150 | 4,826 |
Less: accumulated depreciation |  |  | 1,329 | 1,247 |
Property, plant and equipment, net |  |  | 3,821 | 3,579 |
Plant Held for Future Use Amount |  |  | 17 |  |
Impairment of Long-Lived Assets Held-for-use |  |  | 0 | 6 | 0
Delmarva Power & Light Company [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 4,195 | 3,875 |
Delmarva Power & Light Company [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Delmarva Power & Light Company [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 70 years |  |
Delmarva Power & Light Company [Member] | Gas Distribution Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 651 | 614 |
Delmarva Power & Light Company [Member] | Gas Distribution Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Delmarva Power & Light Company [Member] | Gas Distribution Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Delmarva Power & Light Company [Member] | Common—electric and gas |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 136 | 117 |
Delmarva Power & Light Company [Member] | Common—electric and gas | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Delmarva Power & Light Company [Member] | Common—electric and gas | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 75 years |  |
Delmarva Power & Light Company [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 151 | 205 |
Delmarva Power & Light Company [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [13] |  | $ 17 | 15 |
Delmarva Power & Light Company [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 10 years |  |
Delmarva Power & Light Company [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 43 years |  |
Atlantic City Electric Company [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 4,103 | 3,772 |
Less: accumulated depreciation |  |  | 1,137 | 1,066 |
Property, plant and equipment, net |  |  | 2,966 | 2,706 |
Plant Held for Future Use Amount |  |  | 28 |  |
Impairment of Long-Lived Assets Held-for-use |  |  | 0 | 7 | $ 0
Atlantic City Electric Company [Member] | Electric—transmission and distribution |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 3,866 | 3,607 |
Atlantic City Electric Company [Member] | Electric—transmission and distribution | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 5 years |  |
Atlantic City Electric Company [Member] | Electric—transmission and distribution | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 60 years |  |
Atlantic City Electric Company [Member] | Construction work in progress |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment |  |  | $ 209 | 138 |
Atlantic City Electric Company [Member] | Other Property Plant and Equipment |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Total property, plant and equipment | [14] |  | $ 28 | $ 27 |
Atlantic City Electric Company [Member] | Other Property Plant and Equipment | Minimum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 13 years |  |
Atlantic City Electric Company [Member] | Other Property Plant and Equipment | Maximum [Member] |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Average Service Life (years) |  |  | 15 years |  |
[1] | Includes accumulated amortization of nuclear fuel in the reactor core at Generation of $2,969 million and $3,159 million as of December 31, 2018 and 2017, respectively.
[2] | Includes nuclear fuel that is in the fabrication and installation phase of $1,004 million and $1,196 million at December 31, 2018 and 2017, respectively.
[3] | Includes Generation’s buildings under capital lease with a net carrying value of $5 million and $7 million at December 31, 2018 and 2017, respectively. The original cost basis of the buildings was $47 million as of both December 31, 2018 and 2017, and total accumulated amortization was $42 million and $40 million, as of December 31, 2018 and 2017, respectively. Also includes ComEd’s buildings under capital lease with a net carrying value at both December 31, 2018 and 2017 of $7 million. The original cost basis of the buildings was $8 million and total accumulated amortization was $1 million as of both December 31, 2018 and 2017. Includes land held for future use and non-utility property at ComEd, PECO, BGE, Pepco, DPL and ACE of $39 million, $19 million, $25 million, $61 million, $17 million and $28 million, respectively, at December 31, 2018.
[4] | Includes accumulated amortization of nuclear fuel in the reactor core of $2,969 million and $3,159 million as of December 31, 2018 and 2017, respectively
[5] | Includes nuclear fuel that is in the fabrication and installation phase of $1,004 million and $1,196 million at December 31, 2018 and 2017, respectively
[6] | Includes buildings under capital lease with a net carrying value of $5 million and $7 million at December 31, 2018 and 2017, respectively. The original cost basis of the buildings was $47 million as of both December 31, 2018 and 2017, and total accumulated amortization was $42 million and $40 million, as of December 31, 2018 and 2017, respectively.
[7] | Includes buildings under capital lease with a net carrying value at both December 31, 2018 and 2017 of $7 million. The original cost basis of the buildings was $8 million and total accumulated amortization was $1 million as of both December 31, 2018 and 2017
[8] | Represents land held for future use and non-utility property.
[9] | Represents land held for future use and non-utility property.
[10] | Represents plant held for future use and non-utility property
[11] | Represents plant held for future use and non-utility property.
[12] | Represents plant held for future use and non-utility property.
[13] | Represents plant held for future use and non-utility property.
[14] | Represents plant held for future use and non-utility property.

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