Capitalization - Significant Debt Covenants (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Maximum ratio of consolidated debt to consolidated total capital	0.53
CECONY
Debt Instrument [Line Items]
Maximum ratio of consolidated debt to consolidated total capital	0.54
Term Loan
Debt Instrument [Line Items]
Debt instrument, face amount	$ 825,000,000
Debt term	2 years
Maximum ratio of consolidated debt to consolidated total capital	0.65
Covenant principal balance amount limit	$ 150,000,000
Term Loan | CECONY
Debt Instrument [Line Items]
Covenant principal balance amount limit	$ 150,000,000
Notes
Debt Instrument [Line Items]
Maximum ratio of consolidated debt to consolidated total capital	0.675
Covenant principal balance amount limit	$ 100,000,000
Notes | CECONY
Debt Instrument [Line Items]
Covenant principal balance amount limit	100,000,000
Tax-Exempt Debt | CECONY
Debt Instrument [Line Items]
Debt instrument, face amount	$ 450,000,000
Maximum ratio of consolidated debt to consolidated total capital	0.65