Other Postretirement Benefits - Schedule of Expected Benefit Payments (Detail) (Other Postretirement Benefits [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
2015 - Benefit Payments	$ 99
2016 - Benefit Payments	95
2017 - Benefit Payments	94
2018 - Benefit Payments	92
2019 - Benefit Payments	89
2020-2024 - Benefit Payments	419
CECONY [Member]
Defined Benefit Plan Disclosure [Line Items]
2015 - Benefit Payments	89
2016 - Benefit Payments	85
2017 - Benefit Payments	84
2018 - Benefit Payments	82
2019 - Benefit Payments	79
2020-2024 - Benefit Payments	$ 364

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Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ 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=35743120&loc=d3e1928-114920

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Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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+ References

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Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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+ References

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