Derivative Instruments and Hedging Activities - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Investment Holdings [Line Items]
Energy supply and hedging activities credit exposure total	$ 166
Makeup of net credit exposure with commodity exchange brokers	77
Makeup of net credit exposure independent system operators	76
Makeup of net credit exposure with investment-grade counterparties	8
Makeup of net credit exposure non-investment grade/non-rated counterparties	5
CECONY
Investment Holdings [Line Items]
Energy supply and hedging activities credit exposure total	$ 21

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Credit exposure nonrated counterparties

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- Definition

Maximum Potential Future Exposure On Credit Risk Derivatives With Commodity Exchange Brokers

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Maximum Potential Future Exposure On Credit Risk Derivatives With Investment Grade Counterparties

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Maximum potential amount of future undiscounted payments that could be required under the credit derivative, before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4K

-Subparagraph (b)(1)

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Credit Derivative

-URI http://asc.fasb.org/extlink&oid=6854095

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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.

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