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Debt and Credit Agreements - Summary of Credit Facility Thresholds (Details) | 12 Months Ended
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Dec. 31, 2018
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.50
Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 27.50%
London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 127.50%
Exelon Generation Co L L C [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 3.00
Exelon Generation Co L L C [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 27.50%
Exelon Generation Co L L C [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 127.50%
Commonwealth Edison Co [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
Commonwealth Edison Co [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 7.50%
Commonwealth Edison Co [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 107.50%
PECO Energy Co [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
PECO Energy Co [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 0.00%
PECO Energy Co [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 90.00%
Baltimore Gas and Electric Company [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
Baltimore Gas and Electric Company [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 0.00%
Baltimore Gas and Electric Company [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 100.00%
Potomac Electric Power Company [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
Potomac Electric Power Company [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 7.50%
Potomac Electric Power Company [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 107.50%
Delmarva Power & Light Company [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
Delmarva Power & Light Company [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 7.50%
Delmarva Power & Light Company [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 107.50%
Atlantic City Electric Company [Member] |
Line of Credit Facility [Line Items] |
Credit agreement threshold | 2.00
Atlantic City Electric Company [Member] | Prime Rate [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 7.50%
Atlantic City Electric Company [Member] | London Interbank Offered Rate (LIBOR) [Member] |
Line of Credit Facility [Line Items] |
Line of Credit Facility, Interest Rate at Period End | 107.50%

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- Definition Description of the conditions for borrowing under the credit facility including the nature of any restrictions. + 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
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- Definition The effective interest rate at the end of the reporting period. + 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
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