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Asset Acquisition, Consideration Transferred

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Asset Acquisition, Consideration Transferred, Common Units, Weighted Average Sales Price

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Asset Acquisition, Consideration Transferred, Equity Interests Issued and Issuable

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Asset Acquisition

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Equity Method Investment, Ownership Percentage Acquired

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Payments To Acquire Asset, Gross

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Number of common units issued of limited liability company (LLC).

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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The number of general partner units issued.

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The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

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Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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Acquisitions - June 2019 Acquisitions (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Jun. 06, 2019	May 11, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Asset Acquisition [Line Items]
Remeasurements of pension and other postretirement benefits related to equity method investments, net of tax			$ 0	$ 0	$ 0	$ 0
June 2019 Acquisition
Asset Acquisition [Line Items]
Consideration transferred	$ 800
Historical carrying value of net assets under common control	90
Remeasurements of pension and other postretirement benefits related to equity method investments, net of tax	6
Capital distribution to general partner	510
Non-cash equity consideration	$ 200
Common units, weighted average sales price (in dollars per unit)	$ 20.68
General partners' capital account, units issued (in shares)	193,424
General Partner \| June 2019 Acquisition
Asset Acquisition [Line Items]
Noncontrolling interest	2.00%
Subsidiary \| Shell Midstream LP Holdings LLC \| June 2019 Acquisition
Asset Acquisition [Line Items]
Common units issued (in shares)	9,477,756
Revolving Credit Facility \| Ten Year Fixed Facility
Asset Acquisition [Line Items]
Debt instrument term					10 years
Revolving Credit Facility \| Shell Treasury Center West Inc \| Ten Year Fixed Facility
Asset Acquisition [Line Items]
Debt instrument term					10 years
Revolving Credit Facility \| Shell Treasury Center West Inc \| Ten Year Fixed Facility \| June 2019 Acquisition
Asset Acquisition [Line Items]
Consideration, cash on hand	$ 600
Debt instrument term		5 years
Explorer
Asset Acquisition [Line Items]
Ownership			38.59%		38.59%		12.62%
Explorer \| June 2019 Acquisition
Asset Acquisition [Line Items]
Equity method investment, ownership interest acquired	25.97%
Ownership			38.59%		38.59%
Colonial Pipeline Company (“Colonial”)
Asset Acquisition [Line Items]
Ownership			16.125%		16.125%		6.00%
Colonial Pipeline Company (“Colonial”) \| June 2019 Acquisition
Asset Acquisition [Line Items]
Equity method investment, ownership interest acquired	10.125%
Ownership			16.125%		16.125%