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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The cash outflow associated with the purchase of or advances to an 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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Acquisitions, Investments and Dispositions - Mountain Valley Pipeline (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity method investment		$ 0	$ 467
Mountain Valley Pipeline \| Maximum
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity interest		$ 4,600
CET Gas \| Mountain Valley Pipeline
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest acquired	12.50%	12.50%
Payments to acquire equity interest	$ 18
Equity method investment		$ 363	$ 98