Junior subordinate notes issued in the form of equity units

No definition available.

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- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Period Type:	instant

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

+ References

+ Details

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- 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

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- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Current fair value of each cash settlement alternative for each freestanding forward contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of shares as a settlement alternative for each freestanding forward contract.

+ References

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

+ References

Reference 1: 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(16)(a))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: 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(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowings from a bank classified as other, maturing within one year or operating cycle, if longer.

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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Debt and Credit Agreements - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2014	Mar. 31, 2017	Mar. 31, 2016	Mar. 23, 2017	Jan. 09, 2017	May 26, 2016	Apr. 01, 2016	Jan. 13, 2016	Jan. 05, 2016	Oct. 23, 2015	Aug. 10, 2013	Jan. 31, 2013	Aug. 01, 2011
Debt Instrument [Line Items]
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Cash, at Fair Value		$ 1,150
Extinguishment of Debt, Amount		11	$ 11
Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes		$ 1,150
Equity Units Issued	23
Debt Instrument, Convertible, Conversion Price	$ 50
Interest Rate	2.50%	3.497%
Minimum [Member] \| Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value		26
Maximum [Member] \| Junior Subordinated Debt [Member]
Debt Instrument [Line Items]
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value		33
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity						$ 600					$ 500
Corporate, Non-Segment [Member]
Debt Instrument [Line Items]
Short-term Bank Loans and Notes Payable				$ 500
Debt Instrument, Interest Rate Terms		LIBOR plus 1%
Pepco Holdings LLC [Member]
Debt Instrument [Line Items]
Short-term Bank Loans and Notes Payable								$ 500
Debt Instrument, Interest Rate Terms		LIBOR plus 1%
Pepco Holdings LLC [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity						$ 900							$ 1,500
Exelon Generation Co L L C [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 100		$ 200		$ 150	$ 100		$ 75