Derivative Instruments and Hedging Activities - Realized and Unrealized Gains or Losses on Commodity Derivatives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	$ 251	$ 191
Total deferred gains/(losses)	384	122
Net deferred gains/(losses)	635	313
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 168	$ 78
Gas purchased for resale
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Operating costs	Operating costs
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 5	$ 18
Other operations and maintenance expense
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Operating costs	Operating costs
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 4	$ 5
Interest Expense (Income), Other, Net
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other interest	Other interest
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 159	$ 52
Non-utility
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	TOTAL OPERATING REVENUES	TOTAL OPERATING REVENUES
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 0	$ 3
Deferred Derivative Gains,Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	168	134
Deferred Derivative Gains, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	83	57
Deferred Derivative Losses, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	(43)	49
Recoverable Energy Costs, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	408	3
Deferred Derivative Losses, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	19	70
CECONY
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	230	175
Total deferred gains/(losses)	347	109
Net deferred gains/(losses)	577	284
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 4	$ 5
CECONY | Gas purchased for resale
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Operating costs	Operating costs
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 0	$ 0
CECONY | Other operations and maintenance expense
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Operating costs	Operating costs
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 4	$ 5
CECONY | Interest Expense (Income), Other, Net
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other interest	Other interest
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 0	$ 0
CECONY | Non-utility
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	TOTAL OPERATING REVENUES	TOTAL OPERATING REVENUES
Pre-tax gain/(loss) recognized in income
Total pre-tax gain/(loss) recognized in income	$ 0	$ 0
CECONY | Deferred Derivative Gains,Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	155	124
CECONY | Deferred Derivative Gains, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	75	51
CECONY | Deferred Derivative Losses, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	(44)	43
CECONY | Recoverable Energy Costs, Current
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	372	0
CECONY | Deferred Derivative Losses, Noncurrent
Pre-tax gains/(losses) deferred in accordance with accounting rules for regulated operations:
Total deferred gains/(losses)	$ 19	$ 66