Capitalization - Additional Information (Details)		12 Months Ended
		Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)
Schedule of Capitalization [Line Items]
Percentage limitation for income available for dividends (not more than)		100.00%
Rolling average calculation of income available for dividends (years)		2 years
Long-term debt, fair value		$ 16,093,000,000	$ 13,856,000,000
Long-term debt		14,774,000,000	12,745,000,000
Non-recourse debt		$ 845,000,000	339,000,000
Ratio of consolidated debt to consolidated total capital		0.51
Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
Transition Bonds, Issued in 2004
Schedule of Capitalization [Line Items]
Long-term debt		$ 11,000,000	15,000,000
Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value		15,457,000,000
Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value		636,000,000
Tax-Exempt Debt
Schedule of Capitalization [Line Items]
Long-term debt	[1]	1,086,000,000	1,086,000,000
Notes
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		$ 100,000,000
Notes | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.675
Term Loan
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		$ 150,000,000
Term Loan | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
CECONY
Schedule of Capitalization [Line Items]
Common stock shares, outstanding | shares		21,976,200
Long-term debt, fair value		$ 13,268,000,000	12,427,000,000
Long-term debt		$ 12,073,000,000	11,437,000,000
Ratio of consolidated debt to consolidated total capital		0.52
CECONY | Maximum
Schedule of Capitalization [Line Items]
Ratio of consolidated debt to consolidated total capital		0.65
Covenant principal balance amount limit		$ 100,000,000
CECONY | Minimum
Schedule of Capitalization [Line Items]
Covenant principal balance amount limit		150,000,000
CECONY | Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value		12,632,000,000
CECONY | Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value		636,000,000
CECONY | Tax-Exempt Debt
Schedule of Capitalization [Line Items]
Tax-exempt debt issued, value		450,000,000
Long-term debt		1,086,000,000	$ 1,086,000,000
CECONY | Tax-Exempt Debt | Level 3
Schedule of Capitalization [Line Items]
Long-term debt		$ 636,000,000

[1] Rates are to be reset weekly or by auction held every 35 days; December 31, 2016 rates shown.