Derivative Instruments and Hedging Activities - Fair Values of Commodity Derivatives Including Offsetting of Assets and Liabilities (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Net fair value derivative assets/(liabilities)
Gross Amounts of Recognized Assets/ (Liabilities)	$ 466,000,000	$ (8,000,000)
Gross Amounts Offset	(237,000,000)	(24,000,000)
Net Amounts of Assets/ (Liabilities)	229,000,000	(32,000,000)
Fair value of derivative assets	85,000,000	77,000,000
CECONY
Net fair value derivative assets/(liabilities)
Gross Amounts of Recognized Assets/ (Liabilities)	294,000,000	25,000,000
Gross Amounts Offset	(214,000,000)	(26,000,000)
Net Amounts of Assets/ (Liabilities)	80,000,000	(1,000,000)
Fair value of derivative assets	80,000,000	56,000,000
Clean Energy Businesses | Interest Rate Swap
Net fair value derivative assets/(liabilities)
Notional amount	982,000,000	1,031,000,000
Fair Value of Derivative Liabilities, Current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(198,000,000)	(289,000,000)
Gross Amounts Offset	166,000,000	137,000,000
Net Amounts of Assets/ (Liabilities)	(32,000,000)	(152,000,000)
Fair Value of Derivative Liabilities, Current | Interest Rate Swap
Fair value of derivative liabilities
Net Amounts of Assets/ (Liabilities)		(20,000,000)
Fair Value of Derivative Liabilities, Current | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(189,000,000)	(131,000,000)
Gross Amounts Offset	160,000,000	43,000,000
Net Amounts of Assets/ (Liabilities)	(29,000,000)	(88,000,000)
Fair Value of Derivative Liabilities, Non-current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(49,000,000)	(94,000,000)
Gross Amounts Offset	36,000,000	10,000,000
Net Amounts of Assets/ (Liabilities)	(13,000,000)	(84,000,000)
Fair Value of Derivative Liabilities, Non-current | Interest Rate Swap
Fair value of derivative liabilities
Net Amounts of Assets/ (Liabilities)		(38,000,000)
Fair Value of Derivative Liabilities, Non-current | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(43,000,000)	(50,000,000)
Gross Amounts Offset	34,000,000	10,000,000
Net Amounts of Assets/ (Liabilities)	(9,000,000)	(40,000,000)
Fair Value of Derivative Liabilities, Held and Used Liabilities
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(247,000,000)	(383,000,000)
Gross Amounts Offset	202,000,000	147,000,000
Net Amounts of Assets/ (Liabilities)	(45,000,000)	(236,000,000)
Fair Value of Derivative Liabilities, Held for Sale Liabilities, Current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(31,000,000)	0
Gross Amounts Offset	6,000,000	0
Net Amounts of Assets/ (Liabilities)	(25,000,000)	0
Fair Value of Derivative Liabilities, Held for Sale Liabilities, Non-Current
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(3,000,000)	0
Gross Amounts Offset	(8,000,000)	0
Net Amounts of Assets/ (Liabilities)	(11,000,000)	0
Fair Value of Derivative Liabilities
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(281,000,000)	(383,000,000)
Gross Amounts Offset	200,000,000	147,000,000
Net Amounts of Assets/ (Liabilities)	(81,000,000)	(236,000,000)
Net fair value derivative assets/(liabilities)
Margin deposit liability	(10,000,000)
Fair Value of Derivative Liabilities | CECONY
Fair value of derivative liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(232,000,000)	(181,000,000)
Gross Amounts Offset	194,000,000	53,000,000
Net Amounts of Assets/ (Liabilities)	(38,000,000)	(128,000,000)
Net fair value derivative assets/(liabilities)
Margin deposit liability	(6,000,000)
Fair Value of Derivative Assets, Current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	378,000,000	285,000,000
Gross Amounts Offset	(332,000,000)	(158,000,000)
Net Amounts of Assets/ (Liabilities)	46,000,000	127,000,000
Fair Value of Derivative Assets, Current | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	350,000,000	135,000,000
Gross Amounts Offset	(312,000,000)	(64,000,000)
Net Amounts of Assets/ (Liabilities)	38,000,000	71,000,000
Fair Value of Derivative Assets, Non-current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	193,000,000	90,000,000
Gross Amounts Offset	(108,000,000)	(13,000,000)
Net Amounts of Assets/ (Liabilities)	85,000,000	77,000,000
Fair Value of Derivative Assets, Non-current | Interest Rate Swap
Fair value of derivative assets
Net Amounts of Assets/ (Liabilities)		4,000,000
Net fair value derivative assets/(liabilities)
Fair value of derivative assets	75,000,000
Fair Value of Derivative Assets, Non-current | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	176,000,000	71,000,000
Gross Amounts Offset	(96,000,000)	(15,000,000)
Net Amounts of Assets/ (Liabilities)	80,000,000	56,000,000
Fair Value of Derivative Assets, Held and Used Assets
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	571,000,000	375,000,000
Gross Amounts Offset	(440,000,000)	(171,000,000)
Net Amounts of Assets/ (Liabilities)	131,000,000	204,000,000
Fair Value of Derivative Assets, Held-For-Sale Assets, Current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	93,000,000	0
Gross Amounts Offset	(8,000,000)	0
Net Amounts of Assets/ (Liabilities)	85,000,000	0
Fair Value of Derivative Assets, Held-For Sale Assets, Non-Current
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	83,000,000	0
Gross Amounts Offset	11,000,000	0
Net Amounts of Assets/ (Liabilities)	94,000,000	0
Fair Value of Derivative Assets
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	747,000,000	375,000,000
Gross Amounts Offset	(437,000,000)	(171,000,000)
Net Amounts of Assets/ (Liabilities)	310,000,000	204,000,000
Net fair value derivative assets/(liabilities)
Margin deposits	13,000,000	1,000,000
Fair Value of Derivative Assets | Interest Rate Swap
Net fair value derivative assets/(liabilities)
Fair value of derivative assets	31,000,000
Fair Value of Derivative Assets | CECONY
Fair value of derivative assets
Gross Amounts of Recognized Assets/ (Liabilities)	526,000,000	206,000,000
Gross Amounts Offset	(408,000,000)	(79,000,000)
Net Amounts of Assets/ (Liabilities)	118,000,000	127,000,000
Net fair value derivative assets/(liabilities)
Margin deposits	$ 13,000,000	$ 0