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Equity Method Investment, Ownership Percentage, Expected Increase (Decrease)

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Equity Method Investment, Project Percent Completion

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Equity Method Investment, Realized Gain (Loss) On Disposal, Before Tax

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Increase (Decrease) In Deferred Tax Assets

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Long Term Firm Transportation Contract Period

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Number Of Miles In Pipeline Construction

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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Amount of gain (loss) on sale or disposal of an equity method investment.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Fair value portion of investments accounted under the equity method.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount after tax of loss recognized that results from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Summary of Significant Accounting Policies and Other Matters - Investments (Details) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2021 USD ($)	Mar. 31, 2022 USD ($) mi	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 30, 2021 USD ($)	Feb. 28, 2021 USD ($)	Dec. 30, 2020 USD ($)	Jan. 31, 2016
Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Goodwill, impairment loss			$ 343
Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage			50.00%
Stagecoach Gas Services LLC
Schedule of Equity Method Investments [Line Items]
Loss on sale of investment (pre-tax)				$ 212
Loss on sale of investment				$ 147
Equity method investments			$ 667				$ 839
Goodwill, impairment loss			172
Goodwill, impairment loss, after-tax			$ 120
Stagecoach Gas Services LLC \| Con Edison Transmission \| Subsidiaries
Schedule of Equity Method Investments [Line Items]
Proceeds from sale	$ 1,225
Ownership percentage	50.00%
Stagecoach Gas Services LLC \| CET Gas \| Subsidiaries
Schedule of Equity Method Investments [Line Items]
Proceeds from sale	$ 629
Mountain Valley Pipeline LLC \| Con Edison Gas Pipeline and Storage, LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage		10.00%		10.20%	11.30%
Impairment charge				$ 231	$ 320
Equity method investments				$ 530
Long Term Firm Transportation Contract Period				20 years
Cash Flows Discount Rate				8.30%
Equity Method Investment, Other Than Temporary Impairment, Net Of Tax				$ 162	223
Equity Method Investments, Fair Value Disclosure				111	342	$ 342		$ 662
Deferred Tax Assets, Net		$ 130		130	$ 53
Increase (Decrease) In Deferred Tax Assets				$ 77
Number Of Miles In Pipeline Construction \| mi		300
Equity Method Investment, Ownership Percentage, Expected Increase (Decrease)		8.00%
Equity Method Investment, Project Percent Completion				94.00%	92.00%
Mountain Valley Pipeline LLC \| Con Edison Gas Pipeline and Storage, LLC \| Mountain Valley Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Ownership percentage									12.50%