XML 244 R126.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Debt and Credit Agreements - Commercial Paper Borrowings Outstanding (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 30, 2018 | Jun. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016
--- | --- | --- | --- | --- | --- | ---
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [1] | $ 9,704 |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.15% |  |  | 1.24% |  | 1.12% |
Letters of Credit Outstanding, Amount |  | $ 1,696 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 135 |  |  | $ 128 |  |  |
Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3],[4] | 9,000 |  |  | 9,450 |  |  |
Outstanding commercial paper |  | 89 |  |  | 427 |  |  |
Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  |  |  |  |  |  |  | $ 500
Exelon Corporate [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  | 9 |  |  |  |  |  |
Exelon Corporate [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 600 |  |  | 600 | [4] |  |
Outstanding commercial paper |  | $ 0 |  |  | $ 0 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 1.93% |  |  | 1.16% |  |  |
Exelon Generation Co L L C [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 200 |  | $ 45 |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 1.96% |  |  | 1.23% |  | 1.14% |
Credit facility agreements with minority and community banks |  | $ 49 | $ 75 |  | $ 49 |  |  |
Exelon Generation Co L L C [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 5,300 |  |  | 5,300 | [4] |  |
Outstanding commercial paper |  | $ 0 |  |  | $ 0 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 1.96% |  |  | 1.23% |  |  |
Exelon Generation Co L L C [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  | $ 545 |  |  | $ 480 |  |  |
Exelon Generation Co L L C [Member] | Secured Debt [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  | 159 |  |  | $ 179 |  |  |
Exelon Generation Co L L C [Member] | Letter of Credit [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  | $ 5 |  |  |  |  |  |
Commonwealth Edison Co [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.14% |  |  | 1.24% |  |  |
Letters of Credit Outstanding, Amount |  | $ 2 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 33 |  |  | $ 34 |  |  |
Commonwealth Edison Co [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 1,000 |  |  | 1,000 | [4] |  |
Outstanding commercial paper |  | $ 0 |  |  | $ 0 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.14% |  |  | 1.24% |  |  |
PECO Energy Co [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.24% |  |  | 1.13% |  |  |
Letters of Credit Outstanding, Amount |  | $ 0 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 34 |  |  | $ 34 |  |  |
PECO Energy Co [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 600 |  |  | 600 | [4] |  |
Outstanding commercial paper |  | $ 0 |  |  | $ 0 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.24% |  |  | 1.13% |  |  |
Baltimore Gas and Electric Company [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.18% |  |  | 1.28% |  | 0.95% |
Letters of Credit Outstanding, Amount |  | $ 1 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 5 |  |  | $ 5 |  |  |
Baltimore Gas and Electric Company [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 600 |  |  | 600 | [4] |  |
Outstanding commercial paper |  | $ 35 |  |  | $ 77 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.18% |  |  | 1.28% |  |  |
Baltimore Gas and Electric Company [Member] | Letter of Credit [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  | $ 2 |  |  |  |  |  |
Pepco Holdings LLC [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 1,500 |  |  |  |  |  |
Potomac Electric Power Company [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.24% |  |  | 1.06% |  | 0.90% |
Letters of Credit Outstanding, Amount |  | $ 8 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 5 |  |  | $ 2 |  |  |
Potomac Electric Power Company [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 300 |  |  | 500 | [4] |  |
Outstanding commercial paper |  | $ 40 |  |  | $ 26 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.24% |  |  | 1.06% |  |  |
Delmarva Power & Light Company [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.07% |  |  | 1.48% |  |  |
Letters of Credit Outstanding, Amount |  | $ 1 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 5 |  |  | $ 2 |  |  |
Delmarva Power & Light Company [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 300 |  |  | 500 | [4] |  |
Outstanding commercial paper |  | $ 0 |  |  | $ 216 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.07% |  |  | 1.48% |  |  |
Atlantic City Electric Company [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.21% |  |  | 1.43% |  |  |
Letters of Credit Outstanding, Amount |  | $ 0 |  |  |  |  |  |
Credit facility agreements with minority and community banks |  | 5 |  |  | $ 2 |  |  |
Atlantic City Electric Company [Member] | Commercial Paper [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity | [2],[3] | 300 |  |  | 350 | [4] |  |
Outstanding commercial paper |  | $ 14 |  |  | $ 108 |  |  |
Average Interest Rate on Commercial Paper Borrowings |  | 2.21% |  |  | 1.43% |  |  |
Maximum [Member] | Pepco Holdings LLC [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 900 |  |  |  |  |  |
Maximum [Member] | Delmarva Power & Light Company [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | 0 |  |  |  |  |  |
Maximum [Member] | Atlantic City Electric Company [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |
Short-term Debt [Line Items] |  |  |  |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 0 |  |  |  |  |  |
[1] | Excludes $135 million of credit facility agreements arranged at minority and community banks at Generation, ComEd, PECO, BGE, Pepco, DPL and ACE with aggregate commitments of $49 million, $33 million, $34 million, $5 million, $5 million, $5 million and $5 million, respectively. These facilities expire on October 11, 2019. These facilities are solely utilized to issue letters of credit. As of December 31, 2018, letters of credit issued under these facilities totaled $5 million and $2 million for Generation and BGE, respectively.
[2] | At December 31, 2018, excludes $135 million of credit facility agreements arranged at minority and community banks at Generation, ComEd, PECO, BGE, Pepco, DPL and ACE with aggregate commitments of $49 million, $33 million, $34 million, $5 million, $5 million, $5 million and $5 million, respectively. These facilities expire on October 11, 2019. These facilities are solely utilized to issue letters of credit. At December 31, 2017, excludes $128 million of credit facility agreements arranged at minority and community banks at Generation, ComEd, PECO, BGE, Pepco, DPL and ACE with aggregate commitments of $49 million, $34 million, $34 million, $5 million, $2 million, $2 million, and $2 million, respectively.
[3] | Excludes $545 million and $480 million in bilateral credit facilities at December 31, 2018 and 2017, respectively, and $159 million and $179 million in credit facilities for project finance at December 31, 2018 and 2017, respectively. These credit facilities do not back Generation's commercial paper program.
[4] | Pepco, DPL and ACE's revolving credit facility is subject to available borrowing capacity. The borrowing capacity may be increased or decreased during the term of the facility, except that (i) the sum of the borrowing capacity must equal the total amount of the facility, and (ii) the aggregate amount of credit used at any given time by each of Pepco, DPL or ACE may not exceed $900 million or the maximum amount of short-term debt the company is permitted to have outstanding by its regulatory authorities. The total number of the borrowing reallocations may not exceed eight per year during the term of the facility.

X
- Definition Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(a)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(2)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_CommercialPaper
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShortTermDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average interest rate of short-term debt outstanding calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_ShortTermDebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=us-gaap_CommercialPaperMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidatedEntitiesAxis=us-gaap_ParentCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
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: | 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: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |