Other Postretirement Benefits - Schedule of Change of Assumed Health Care Cost Trend Rate (Details) - Other Postretirement Benefits $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Increase
Effect on accumulated other postretirement benefit obligation	$ (4)
Effect on service cost and interest cost components for 2016	1
Decrease
Effect on accumulated other postretirement benefit obligation	26
Effect on service cost and interest cost components for 2016	0
CECONY
Increase
Effect on accumulated other postretirement benefit obligation	(24)
Effect on service cost and interest cost components for 2016	(1)
Decrease
Effect on accumulated other postretirement benefit obligation	41
Effect on service cost and interest cost components for 2016	$ 1

Defined Benefit Plan, Effect of One Percentage Point Decrease [Abstract]

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- Definition

Defined Benefit Plan, Effect of One Percentage Point Increase [Abstract]

+ References

No definition available.

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- Definition

Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ 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 (m)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

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