Accounts Receivable (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Accounts Notes And Loans Receivable Net Current [Abstract]
Allowance for uncollectible accounts	$ 229	$ 228
Accounts Receivable Additional Disclosures [Abstract]
Accounts receivable, pledged under accounts receivable agreement	225	225
Gross Accounts Receivable Pledged as Collateral	309	346
Exelon Generation Co L L C [Member]
Accounts Notes And Loans Receivable Net Current [Abstract]
Allowance for uncollectible accounts	30	32
Commonwealth Edison Co [Member]
Accounts Notes And Loans Receivable Net Current [Abstract]
Allowance for uncollectible accounts	78	80
PECO Energy Co [Member]
Accounts Notes And Loans Receivable Net Current [Abstract]
Allowance for uncollectible accounts	121	116
Accounts Receivable Additional Disclosures [Abstract]
Accounts receivable, pledged under accounts receivable agreement	225	225
Gross Accounts Receivable Pledged as Collateral	309	346
Financing Receivable Recorded Investment [Line Items]
Installment plan receivables	24	22
Installment plan receivables uncollectible accounts reserve	21	19
PECO Energy Co [Member] \| Low Risk [Member]
Financing Receivable Recorded Investment [Line Items]
Installment plan receivables uncollectible accounts reserve	0	0
PECO Energy Co [Member] \| Low To Medium Risk [Member]
Financing Receivable Recorded Investment [Line Items]
Installment plan receivables uncollectible accounts reserve	1	1
PECO Energy Co [Member] \| Medium Risk [Member]
Financing Receivable Recorded Investment [Line Items]
Installment plan receivables uncollectible accounts reserve	4	5
PECO Energy Co [Member] \| High Risk [Member]
Financing Receivable Recorded Investment [Line Items]
Installment plan receivables uncollectible accounts reserve	$ 16	$ 13

A contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, accounts receivable (with terms exceeding one year), notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets.

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Balance Type:	debit
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- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ 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.

+ Details

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- Details

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- Details

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- Definition

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 4
-Article 5

+ Details

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- Definition

The carrying amount, as of the date of the latest financial statement presented, of finance receivables which are owned but transferred to serve as collateral for the payment of the related debt obligation, primarily a secured borrowing or repurchase agreement, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 140
-Paragraph 17
-Subparagraph a(2)

+ Details

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- Definition

The sum of the fair values, as of the date of each statement of financial position presented, of assets which are owned but transferred to serve as collateral for the payment of debt obligations, primarily secured borrowings, repurchase agreements or other current or potential obligations, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 140
-Paragraph 15
-Subparagraph a

+ Details

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