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Acquisitions, Divestitures and Asset Impairments (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		9 Months Ended
	Apr. 30, 2020	Feb. 29, 2020	Dec. 31, 2020	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Payments to acquire businesses					$ 310	$ 47
Proceeds from sale of assets					$ 246	$ 8
Level 3 \| Measurement Input, Discount Rate \| Valuation Technique, Discounted Cash Flow
Business Acquisition [Line Items]
Discount rate, asset impairment analysis, cost of capital, theoretical market participant					14.00%
(Gains)/losses on asset sales and asset impairments, net
Business Acquisition [Line Items]
Non-cash impairment losses upon classification to assets held for sale				$ 167
Non-cash impairment losses, long-lived assets					$ 446
Transportation and Facilities Segments
Business Acquisition [Line Items]
Non-cash impairment losses, held and used					648
FM Gathering LLC
Business Acquisition [Line Items]
Payments to acquire businesses		$ 300
Property and equipment acquired					115
Intangible assets acquired					$ 187
FM Gathering LLC \| Minimum \| Level 3 \| Measurement Input, Discount Rate \| Valuation Technique, Discounted Cash Flow
Business Acquisition [Line Items]
Discount rate, intangible assets, estimate of risk, theoretical market participant					18.00%
FM Gathering LLC \| Maximum \| Level 3 \| Measurement Input, Discount Rate \| Valuation Technique, Discounted Cash Flow
Business Acquisition [Line Items]
Discount rate, intangible assets, estimate of risk, theoretical market participant					19.00%
Saddlehorn Pipeline Company, LLC
Business Acquisition [Line Items]
Ownership percentage sold		10.00%
Proceeds from sale of interest in unconsolidated entity		$ 78
Saddlehorn Pipeline Company, LLC \| Gain on/(impairment of) investments in unconsolidated entities, net
Business Acquisition [Line Items]
Gain on sale of investment in unconsolidated entity		$ 21
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Other current assets
Business Acquisition [Line Items]
Assets held for sale					$ 224
Los Angeles Basin Crude Oil Terminals \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Facilities \| Subsequent Event
Business Acquisition [Line Items]
Proceeds from sale of assets			$ 200
NGL Terminals \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Facilities
Business Acquisition [Line Items]
Proceeds from sale of assets	$ 163