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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Variable Interest Entities (Pipeline Investments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Variable Interest Entities [Line Items]
Net (Loss) Income	$ (80)	$ 50	$ (2,004)	$ 137
Investments in joint ventures	924		924		$ 1,936
VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in joint ventures	$ 488		$ 488		1,479
ACP
Variable Interest Entities [Line Items]
Ownership percentage	47.00%		47.00%
ACP \| VIE not primary beneficiary
Variable Interest Entities [Line Items]
Net (Loss) Income	$ (163)	$ 65	$ (4,505)	$ 178
Investments in joint ventures	$ (927)		$ (927)		1,179
Constitution
Variable Interest Entities [Line Items]
Ownership percentage	24.00%		24.00%
Pipeline Investments \| VIE not primary beneficiary
Variable Interest Entities [Line Items]
Investments in joint ventures	$ (927)		$ (927)		$ 1,179