XML 305 R187.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Supplemental Financial Information Supplemental Financial Information - Summary of Taxes other than income (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Mar. 23, 2016 | Dec. 31, 2016 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | $ 919 | $ 898 | $ 753
Property |  |  |  | 557 | 545 | 483
Payroll |  |  |  | 247 | 230 | 226
Other |  |  |  | 60 | 58 | 114
Total taxes other than income |  |  |  | 1,783 | 1,731 | 1,576
Exelon Generation Co L L C [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 114 | 126 | 122
Property |  |  |  | 273 | 269 | 246
Payroll |  |  |  | 130 | 121 | 117
Other |  |  |  | 39 | 39 | 21
Total taxes other than income |  |  |  | 556 | 555 | 506
Commonwealth Edison Co [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 243 | 240 | 242
Property |  |  |  | 30 | 28 | 27
Payroll |  |  |  | 27 | 26 | 28
Other |  |  |  | 11 | 2 | (4)
Total taxes other than income |  |  |  | 311 | 296 | 293
PECO Energy Co [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 131 | 125 | 136
Property |  |  |  | 15 | 14 | 13
Payroll |  |  |  | 16 | 15 | 15
Other |  |  |  | 1 | 0 | 0
Total taxes other than income |  |  |  | 163 | 154 | 164
Baltimore Gas and Electric Company [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 94 | 89 | 85
Property |  |  |  | 143 | 132 | 123
Payroll |  |  |  | 17 | 15 | 17
Other |  |  |  | 0 | 4 | 4
Total taxes other than income |  |  |  | 254 | 240 | 229
Pepco Holdings LLC [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 337 | 318 |
Property |  |  |  | 94 | 101 |
Payroll |  |  |  | 24 | 26 |
Other |  |  |  | 0 | 7 |
Total taxes other than income |  |  |  | 455 | 452 |
Pepco Holdings LLC [Member] | Successor [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  | $ 253 |  |  |
Property |  |  | 73 |  |  |
Payroll |  |  | 23 |  |  |
Other |  |  | 5 |  |  |
Total taxes other than income |  |  | $ 354 |  |  |
Pepco Holdings LLC [Member] | Predecessor [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] | $ 78 |  |  |  |
Property |  | 18 |  |  |  |
Payroll |  | 8 |  |  |  |
Other |  | 1 |  |  |  |
Total taxes other than income |  | $ 105 |  |  |  |
Potomac Electric Power Company [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 316 | 300 | 312
Property |  |  |  | 58 | 62 | 53
Payroll |  |  |  | 5 | 6 | 8
Other |  |  |  | 0 | 3 | 4
Total taxes other than income |  |  |  | 379 | 371 | 377
Delmarva Power & Light Company [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 21 | 18 | 18
Property |  |  |  | 32 | 32 | 31
Payroll |  |  |  | 3 | 4 | 5
Other |  |  |  | 0 | 3 | 1
Total taxes other than income |  |  |  | 56 | 57 | 55
Atlantic City Electric Company [Member] |  |  |  |  |  |
Supplemental Statement of Operations Information [Line Items] |  |  |  |  |  |
Utility | [1] |  |  | 0 | 0 | 0
Property |  |  |  | 3 | 3 | 3
Payroll |  |  |  | 2 | 2 | 3
Other |  |  |  | 0 | 1 | 1
Total taxes other than income |  |  |  | $ 5 | $ 6 | $ 7
[1] | Generation’s utility tax represents gross receipts tax related to its retail operations and ComEd’s, PECO’s, BGE’s, Pepco's, DPL's and ACE's utility taxes represent municipal and state utility taxes and gross receipts taxes related to their operating revenues. The offsetting collection of utility taxes from customers is recorded in revenues in the Registrants’ Consolidated Statements of Operations and Comprehensive Income.

X
- Definition Supplemental Statement of Operations Information Line Item + References No definition available. + Details
Name: | exc_SupplementalStatementofOperationsInformationLineItems
Namespace Prefix: | exc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of labor-related expenses classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_OtherLaborRelatedExpenses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A tax based on the assessed value of real estate by the local government. The tax is usually based on the value of property (including the land). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 720 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6419918&loc=d3e35301-107843 + Details
Name: | us-gaap_RealEstateTaxExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_TaxesExcludingIncomeAndExciseTaxes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of tax expense classified as other. + References No definition available. + Details
Name: | us-gaap_TaxesOther
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of operating expense for taxes other than income taxes of regulated operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_UtilitiesOperatingExpenseTaxes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=exc_ExelonGenerationCoLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_CommonwealthEdisonCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_PecoEnergyCoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_BaltimoreGasAndElectricCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_PepcoHoldingsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_SuccessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_PredecessorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_PotomacElectricPowerCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_DelmarvaPowerandLightCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=exc_AtlanticCityElectricCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |