Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

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The cash outflow to purchase long lived physical asset for use in the normal oil and gas operations and to purchase mineral interests in oil and gas properties not intended for resale.

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The liability due as of the balance sheet date for leasebacks accounted for using the deposit method.

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Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

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Commitments and Contingencies, Narrative (Details) $ in Millions		3 Months Ended	4 Months Ended	11 Months Ended	12 Months Ended			17 Months Ended	21 Months Ended	27 Months Ended
	Feb. 01, 2018 USD ($)	Dec. 31, 2017 USD ($) bbl / d renewal MBbls	Dec. 31, 2017 USD ($) bbl / d renewal MBbls	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) bbl / d renewal MBbls	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jan. 01, 2020 USD ($)	Jan. 31, 2018 bbl / d MBbls
Commitments And Contingencies (Textual)
Total project cost		$ 40,010	$ 40,010		$ 40,010	$ 37,733
Contributions					406	4	$ 141
Payments to acquire interest in project					$ 72	0	$ 0
Terminalling Agreement [Member] \| MVP Terminalling, LLC (MVP) [Member]
Commitments And Contingencies (Textual)
Initial term of agreement			12 years
Number of renewal options \| renewal		2	2		2
Duration of renewal option			5 years
MVP Terminal [Member]
Commitments And Contingencies (Textual)
Terminal storage capacity (barrels) \| MBbls		5,000	5,000		5,000
Contributions			$ 81
MVP Terminal [Member] \| Magellan Midstream Partners LP (Magellan) [Member]
Commitments And Contingencies (Textual)
Long term liability		$ 94	$ 94		$ 94
Central Texas Pipeline [Member]
Commitments And Contingencies (Textual)
Undivided interest in project (percent)		40.00%	40.00%		40.00%
Pipeline capacity (barrels per day) \| bbl / d		150,000	150,000		150,000
Payments to acquire interest in project		$ 7
Sunrise Pipeline System [Member] \| Subsequent Event [Member]
Commitments And Contingencies (Textual)
Undivided interest in project (percent)											20.00%
Pipeline capacity (barrels per day) \| bbl / d											500,000
Payments to acquire interest in project	$ 34
Colorado City Storage Tanks [Member] \| Subsequent Event [Member]
Commitments And Contingencies (Textual)
Terminal storage capacity (barrels) \| MBbls											270
Construction in Progress [Member]
Commitments And Contingencies (Textual)
Total project cost		1,274	$ 1,274		$ 1,274	$ 730
Construction in Progress [Member] \| MVP Terminal [Member]
Commitments And Contingencies (Textual)
Total project cost		174	174		174
Expected Impact [Member] \| MVP Terminal [Member]
Commitments And Contingencies (Textual)
Contributions										$ 420
Expected Impact [Member] \| Central Texas Pipeline [Member]
Commitments And Contingencies (Textual)
Payments to acquire interest in project									$ 170
Expected Impact [Member] \| Sunrise Pipeline System [Member]
Commitments And Contingencies (Textual)
Payments to acquire interest in project				$ 101				$ 135
Minimum [Member]
Commitments And Contingencies (Textual)
Range of possible loss contingency		0	0		0
Minimum [Member] \| Expected Impact [Member] \| Construction in Progress [Member] \| MVP Terminal [Member]
Commitments And Contingencies (Textual)
Total project cost										840
Maximum [Member]
Commitments And Contingencies (Textual)
Range of possible loss contingency		$ 200	$ 200		$ 200
Maximum [Member] \| Expected Impact [Member] \| Construction in Progress [Member] \| MVP Terminal [Member]
Commitments And Contingencies (Textual)
Total project cost										$ 1,400
Valero Energy Corporation [Member] \| MVP Terminal [Member]
Commitments And Contingencies (Textual)
Terminal storage capacity (barrels) \| MBbls		4,000	4,000		4,000
MVP Terminalling, LLC (MVP) [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member]
Commitments And Contingencies (Textual)
Membership interest (percent)			50.00%