Other Postretirement Benefits - Schedule of Expected Benefit Payments (Detail) (Other Postretirement Benefits [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Schedule Of Other Postretirement Benefits [Line Items]
2013 - BENEFIT PAYMENTS	$ 101
2014 - BENEFIT PAYMENTS	101
2015 - BENEFIT PAYMENTS	101
2016 - BENEFIT PAYMENTS	98
2017 - BENEFIT PAYMENTS	97
2018-2022 - BENEFIT PAYMENTS	452
CECONY [Member]
Schedule Of Other Postretirement Benefits [Line Items]
2013 - BENEFIT PAYMENTS	91
2014 - BENEFIT PAYMENTS	90
2015 - BENEFIT PAYMENTS	89
2016 - BENEFIT PAYMENTS	87
2017 - BENEFIT PAYMENTS	86
2018-2022 - BENEFIT PAYMENTS	$ 389

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Amount of benefits expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

+ Details

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- Definition

Amount of benefits expected to be paid in the next fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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Amount of benefits expected to be paid in the fifth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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Amount of benefits expected to be paid in the fourth fiscal year following the latest fiscal year from a defined benefit plan.

+ References

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Amount of benefits expected to be paid in the third fiscal year following the latest fiscal year from a defined benefit plan.

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Amount of benefits expected to be paid in the second fiscal year following the latest fiscal year from a defined benefit plan.

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