Phillips 66 Partners (PSXP) 10-K 24 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jan. 29, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36011
Entity Registrant Name	Phillips 66 Partners LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	38-3899432
Entity Address, Address Line One	2331 CityWest Blvd.
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77042
City Area Code	855
Local Phone Number	283-9237
Title of 12(b) Security	Common Units, Representing Limited Partner Interests
Trading Symbol	PSXP
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2,104
Entity Common Units, Units Outstanding (in shares)		228,340,146
Documents Incorporated by Reference	None
Entity Central Index Key	0001572910
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues and Other Income
Revenues	$ 1,038	$ 1,126	$ 1,045
Equity in earnings of affiliates	493	535	439
Gain from equity interest transfer	84	0	0
Other income	3	6	2
Total Revenues and Other Income	1,618	1,667	1,486
Costs and Expenses
Operating and maintenance expenses	342	405	354
Depreciation	135	120	117
Impairments	96	0	0
General and administrative expenses	66	67	64
Taxes other than income taxes	40	39	35
Interest and debt expense	121	108	115
Other expenses	7	2	1
Total costs and expenses	807	741	686
Income before income taxes	811	926	800
Income tax expense	3	3	4
Net Income	808	923	796
Less: Net income attributable to noncontrolling interest	17	0	0
Net Income Attributable to the Partnership	791	923	796
Less: Preferred unitholders’ interest in net income attributable to the Partnership	41	37	37
Less: General partner’s interest in net income attributable to the Partnership	0	140	240
Limited Partners’ Interest in Net Income Attributable to the Partnership	$ 750	$ 746	$ 519
Common Units
Net Income Attributable to the Partnership Per Limited Partner Unit (dollars)
Common units—basic (in usd per share)	$ 3.29	$ 4.45	$ 4.22
Common units—diluted (in usd per share)	$ 3.27	$ 4.29	$ 4
Weighted-Average Limited Partner Units Outstanding (thousands)
Common units—basic (in shares)	228,333,213	167,655,306	122,768,582
Common units—diluted (in shares)	242,153,000	181,475,000	136,588,000
Third Party
Revenues and Other Income
Revenues	$ 30	$ 29	$ 33
Affiliated Entity
Revenues and Other Income
Revenues	$ 1,008	$ 1,097	$ 1,012

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 808	$ 923	$ 796
Defined benefit plans
Plan sponsored by equity affiliates, net of income taxes	0	0	0
Other comprehensive income	0	0	0
Comprehensive Income	808	923	796
Less: Comprehensive income attributable to noncontrolling interest	17	0	0
Comprehensive Income Attributable to the Partnership	$ 791	$ 923	$ 796

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 7	$ 286
Accounts receivable—related parties	103	101
Accounts receivable—third parties	3	4
Materials and supplies	16	13
Prepaid expenses and other current assets	11	10
Total current assets	140	414
Equity investments	3,244	2,961
Net properties, plants and equipment	3,639	3,349
Goodwill	185	185
Other assets	50	52
Total Assets	7,258	6,961
Liabilities
Accounts payable—related parties	19	19
Accounts payable—third parties	73	84
Accrued interest	35	42
Deferred revenues	27	16
Short-term debt	465	25
Accrued property and other taxes	11	10
Other current liabilities	3	3
Total current liabilities	633	199
Long-term debt	3,444	3,491
Obligation from equity interest transfer	0	343
Other liabilities	90	94
Total Liabilities	4,167	4,127
Equity
Accumulated other comprehensive loss	(1)	(1)
Total Equity	2,798	2,834
Noncontrolling interest	293	0
Total Equity	3,091	2,834
Total Liabilities and Equity	7,258	6,961
Public | Preferred Unitholders Public
Equity
Preferred unitholders (2020 and 2019—13,819,791 units issued and outstanding)	749	746
Total Equity	749	746
Public | Common Units
Equity
Common unitholders	2,706	2,717
Total Equity	2,706	2,717
Non-public | Common Units | Phillips 66
Equity
Common unitholders	(656)	(628)
Total Equity	$ (656)	$ (628)

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - shares	Dec. 31, 2020	Dec. 31, 2019
Public
Preferred units, issued (in shares)	13,819,791	13,819,791
Preferred units, outstanding (in shares)	13,819,791	13,819,791
Common Units | Public
Common units issued (in shares)	58,580,009	58,539,439
Common units outstanding (in shares)	58,580,009	58,539,439
Common Units | Non-public | Phillips 66
Common units issued (in shares)	169,760,137	169,760,137
Common units outstanding (in shares)	169,760,137	169,760,137

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows From Operating Activities
Net Income	$ 808	$ 923	$ 796
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation	135	120	117
Impairments	96	0	0
Undistributed equity earnings	7	(3)	(5)
Gain from equity interest transfer	(84)	0	0
Other	8	10	(36)
Working capital adjustments
Accounts receivable	(1)	(11)	(8)
Materials and supplies	(1)	0	0
Prepaid expenses and other current assets	(1)	10	(11)
Accounts payable	(16)	7	11
Accrued interest	(7)	5	2
Deferred revenues	11	(45)	30
Other accruals	0	0	(4)
Net Cash Provided by Operating Activities	955	1,016	892
Cash Flows From Investing Activities
Cash capital expenditures and investments	(910)	(1,095)	(738)
Advances/loans—related party	0	(95)	0
Collection of advances/loans—related party	0	95	0
Liberty acquisition	(75)	0	0
Return of investment from equity affiliates	177	67	43
Proceeds from sale of equity interest	0	81	0
Net Cash Used in Investing Activities	(808)	(947)	(695)
Cash Flows From Financing Activities
Issuance of debt	415	1,758	675
Repayment of debt	(25)	(1,286)	(575)
Issuance of common units	2	169	128
Debt issuance costs	0	(8)	0
Net proceeds from equity interest transfer	40	342	0
Proceeds from noncontrolling interest	3	0	0
Distributions to noncontrolling interest	(32)	0	0
Other contributions from (distributions to) Phillips 66	8	(3)	4
Net Cash Provided by (Used in) Financing Activities	(426)	216	(381)
Net Change in Cash and Cash Equivalents	(279)	285	(184)
Cash and cash equivalents at beginning of period	7	286	1
Cash and Cash Equivalents at End of Period	286	1	185
Preferred Unitholders Public
Cash Flows From Financing Activities
Quarterly distributions to common unitholders/General Partner	(38)	(37)	(37)
Public | Preferred Unitholders Public
Cash Flows From Operating Activities
Net Income	41	37	37
Public | Common Units
Cash Flows From Operating Activities
Net Income	192	252	228
Cash Flows From Financing Activities
Quarterly distributions to common unitholders/General Partner	(205)	(192)	(158)
General Partner
Cash Flows From Operating Activities
Net Income		140	240
Cash Flows From Financing Activities
Quarterly distributions to common unitholders/General Partner	0	(206)	(216)
Phillips 66 | Non-public | Common Units
Cash Flows From Operating Activities
Net Income	558	494	291
Cash Flows From Financing Activities
Quarterly distributions to common unitholders/General Partner	$ (594)	$ (321)	$ (202)

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Noncontrolling Interest	Accum. Other Comprehensive Loss	Cumulative Effect, Period of Adoption, Adjustment	General Partner	General PartnerCumulative Effect, Period of Adoption, Adjustment	Preferred UnitsPublic	Common UnitholdersPublic	Common UnitholdersPublicCumulative Effect, Period of Adoption, Adjustment	Common UnitholdersNon-public	Common UnitholdersNon-publicPhillips 66	Common UnitholdersNon-publicPhillips 66Cumulative Effect, Period of Adoption, Adjustment
Beginning Balance at Dec. 31, 2017	$ 2,161	$ 0	$ (1)	$ 30	$ (1,345)	$ 1	$ 746	$ 2,274	$ 13		$ 487	$ 16
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common units	128							128
Net Income	796				240		37	228			291
Quarterly cash distributions to unitholders and General Partner	(613)				(216)		(37)	(158)			(202)
Other contributions from Phillips 66	7				7
Ending Balance at Dec. 31, 2018	$ 2,509	0	(1)	$ (1)	$ (1,313)		$ 746	$ 2,485	$ (1)		$ 592
Beginning balance (in shares) at Dec. 31, 2017	137,871,801				2,480,051		13,819,791	52,811,822			68,760,137
Units Outstanding
Units issued in a public equity offering (in shares)	2,532,096							2,532,096
Ending balance (in shares) at Dec. 31, 2018	140,403,897				2,480,051		13,819,791	55,343,918			68,760,137
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common units	$ 173							$ 173
Net Income	923				$ 140		$ 37	252			$ 494
Quarterly cash distributions to unitholders and General Partner	(756)				(206)		(37)	(192)			(321)
Conversion of GP economic interest	(4)				1,381						(1,385)
Other contributions from Phillips 66	(10)				(2)						(8)
Ending Balance at Dec. 31, 2019	$ 2,834	0	(1)		$ 0		$ 746	$ 2,717			$ (628)
Units Outstanding
Units issued in a public equity offering (in shares)	3,195,521							3,195,521
Units issued in conversion of GP economic interest (in shares)	98,519,949				(2,480,051)					101,000,000
Ending balance (in shares) at Dec. 31, 2019	242,119,367				0		13,819,791	58,539,439			169,760,137
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common units	$ 2							$ 2
Net Income	808	17					$ 41	192			$ 558
Quarterly cash distributions to unitholders and General Partner	(837)						(38)	(205)			(594)
Transfer of equity interest	305	305
Proceeds from noncontrolling interest	3	3
Distributions to noncontrolling interest	(32)	(32)
Other contributions from Phillips 66	8										8
Ending Balance at Dec. 31, 2020	$ 3,091	$ 293	$ (1)		$ 0		$ 749	$ 2,706			$ (656)
Units Outstanding
Units issued in a public equity offering (in shares)	40,570							40,570
Ending balance (in shares) at Dec. 31, 2020	242,159,937				0		13,819,791	58,580,009			169,760,137

Consolidated Statement of Cha_2

Consolidated Statement of Changes in Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Cash distribution paid per common unit (in USD per share)	$ 3.500	$ 3.400	$ 2.936

Business and Basis of Presentat

Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2020
Description of Business [Abstract]
Business and Basis of Presentation	Note 1—Business and Basis of Presentation Unless otherwise stated or the context otherwise indicates, all references to “Phillips 66 Partners,” “the Partnership,” “us,” “our,” “we,” or similar expressions refer to Phillips 66 Partners LP, including its consolidated subsidiaries. References to Phillips 66 may refer to Phillips 66 and/or its subsidiaries, depending on the context. References to our “General Partner” or “GP” refer to Phillips 66 Partners GP LLC, and references to “Phillips 66 PDI” refer to Phillips 66 Project Development Inc., the Phillips 66 subsidiary that holds a limited partner interest in us and wholly owns our General Partner. Description of the Business We are a Delaware limited partnership formed in 2013 by wholly owned subsidiaries of Phillips 66. We are a growth-oriented master limited partnership formed to own, operate, develop and acquire primarily fee-based midstream assets. Our operations consist of crude oil, refined petroleum products and natural gas liquids (NGL) transportation, terminaling, processing and storage assets. We conduct our operations through both wholly owned and joint venture operations. The majority of our wholly owned assets are associated with, and are integral to the operation of, nine of Phillips 66’s owned or joint venture refineries. Our operations consist of one reportable segment. We primarily generate revenue by providing fee-based transportation, terminaling, processing, storage and fractionation services to Phillips 66 and other customers. Our equity affiliates primarily generate revenue from transporting and terminaling crude oil, refined petroleum products and NGL. Since we do not own any of the crude oil, refined petroleum products and NGL we handle and do not engage in the trading of those commodities, we have limited direct exposure to risks associated with fluctuating commodity prices, although these risks indirectly influence our activities and results of operations over the long term. The COVID-19 pandemic continues to disrupt economic activities globally. Reduced demand for petroleum products has resulted in decreased volumes through logistics infrastructure. The depth and duration of the economic consequences of the COVID-19 pandemic remain unknown. We continuously monitor our asset and investment portfolio for impairments in this challenging business environment. We recorded impairments totaling $96 million in 2020, and additional impairments may be required in the future. Basis of Presentation

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2—Summary of Significant Accounting Policies Consolidation Principles and Investments in Affiliates Our consolidated financial statements include the accounts of majority-owned, controlled subsidiaries. The equity method is used to account for investments in affiliates in which we have the ability to exert significant influence over the affiliates’ operating and financial policies, including any variable interest entities of which we are not the primary beneficiary. Undivided interests in pipelines are consolidated on a proportionate basis. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities. Actual results could differ from these estimates. Common Control Transactions Businesses acquired from Phillips 66 and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with ours at their carrying value. Any difference between carrying value and recognized consideration is treated as a capital transaction. Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows. Revenue Recognition Revenues are primarily recognized for pipeline transportation, terminaling, storage, processing and fractionation services generated under long-term agreements. A significant portion of our revenues are derived from Phillips 66. The majority of these agreements with Phillips 66 are considered operating leases under GAAP. Effective for periods after January 1, 2019, we elected to account for lease and service elements of contracts classified as leases on a combined basis under the provisions of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2016-02, “Leases (Topic 842),” except for leases of processing-type assets, which contain non-ratable fees related to turnaround activity. For these types of leases, we continued to separate the lease and service elements based on relative standalone prices and applied the new lease standard to the lease element and the revenue standard to the service element. For new or modified leases, our determination of lease classification involves estimates, primarily related to the fair value of the leased asset based on comparable replacement cost and obsolescence estimates, and the allocation of contract consideration between the lease and non-lease components based on the relative stand-alone selling price. Revenues from fixed minimum volume commitments are recognized over the performance obligation period for stand-ready service contracts. Revenues from the variable element of these stand-ready contracts and other contracts without fixed elements are recognized based on the actual volumes transported, stored, processed and fractionated at contractual rates because the actual volumes specifically relate to our efforts to transfer the distinct services. Generally, our services are billed and payments are received on a monthly basis. Billings to Phillips 66 for shortfall volumes under its quarterly minimum volume commitments are recorded as “Deferred revenues” in our consolidated balance sheet, as Phillips 66 generally has the right to make up the shortfall volumes in the following four quarters. For the lease element of the contracts, the deferred revenue will be recognized at the earlier of when shortfall volumes are made up, when the make-up rights contractually expire or when we determine the system will not have the necessary capacity to enable a customer to make up the shortfall volumes. For the service element of the contracts, the deferred revenue will be recognized when the performance obligation is complete or it is probable that the shortfall volumes will not be made up. Billings for tolling services relating to maintenance turnaround activities are billed in advance of such activities. These billings are initially recorded as “Deferred revenues” in our consolidated balance sheet and are recognized when the maintenance turnaround activity commences. Deferred revenue relating to maintenance turnaround operating expenses is recognized in the period the work is performed. Deferred revenue relating to capital projects performed concurrently with a maintenance turnaround is recognized ratably over the remaining tolling services agreement once the equipment is placed into service. Cash Equivalents Cash equivalents are highly liquid, short-term investments that are readily convertible to known amounts of cash and will mature within 90 days or less from the date of acquisition. We carry these at cost plus accrued interest, which approximates fair value. Imbalances We do not purchase or produce crude oil, refined petroleum or NGL product inventories. We experience imbalances as a result of variances in meter readings and in other measurement methods, and volume fluctuations within our crude oil, refined petroleum products and NGL systems due to pressure and temperature changes. Certain of our transportation contracts provide for the shipper to pay a contractual loss allowance, which is valued using quoted market prices of the applicable commodity being shipped. These contractual loss allowances, which are received from the shipper irrespective of, and independently calculated from, actual volumetric gains or losses, are recorded as revenue. Any actual volumetric gains or losses are valued using quoted market prices of the applicable commodities and are recorded as decreases or increases to operating and maintenance expenses, respectively. Fair Value Measurements We measure assets and liabilities requiring fair value presentation or disclosure using the price that would be received to sell an asset or paid to transfer a liability (i.e., an exit price), and disclose such amounts according to the quality of valuation inputs under the following hierarchy: Level 1: Quoted prices in an active market for identical assets or liabilities. Level 2: Observable inputs other than quoted prices included within Level 1 for the asset or liability, either directly or indirectly through market-corroborated inputs. Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities. We classify the fair value of an asset or liability based on the lowest level of input significant to its measurement. A fair value initially reported as Level 3 will be subsequently reported as Level 2 if the unobservable inputs become inconsequential to its measurement, or corroborating market data becomes available. Asset and liability fair values initially reported as Level 2 will be subsequently reported as Level 3 if corroborating market data becomes unavailable. The carrying amounts of our trade receivables and payables approximate fair value. Nonrecurring Fair Value Measurements We apply the fair value measurements criteria to determine the fair value of nonfinancial assets and liabilities that are measured at fair value on a nonrecurring basis, primarily asset retirement obligations and, when impaired, long-lived assets. Properties, Plants and Equipment (PP&E) PP&E is recorded at cost. Costs of maintenance and repairs, which are not significant improvements, are expensed when incurred. Depreciation of PP&E is determined by the individual-unit-straight-line method or the group-straight-line method (for those individual units that are highly integrated with other units). Capitalized Interest Interest from external borrowings is capitalized on major projects with an expected construction period of six months or longer. Capitalized interest is added to the cost of the underlying asset’s PP&E or the applicable equity investment and is amortized over the useful life of the asset. Major Maintenance Activities Costs for planned integrity management projects are expensed in the period incurred. These types of costs include inspection services, contractor repair services, materials and supplies, equipment rentals and labor costs. Impairment of PP&E PP&E used in operations are assessed for impairment whenever changes in facts and circumstances indicate a possible significant deterioration in the future cash flows expected to be generated by an asset group. If, upon review, the sum of the undiscounted expected future pretax cash flows of an asset group is less than the carrying value of the asset group, including applicable liabilities, then the carrying value is written down to estimated fair value and the write down is reported as an impairment in the period in which the determination is made. Individual assets are grouped for impairment purposes at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets—generally at the pipeline system, terminal, or processing or fractionation system level. Since there usually is a lack of quoted market prices for our long-lived assets, the fair value of potentially impaired assets is typically determined based on the present value of expected future cash flows using discount rates and other assumptions believed to be consistent with those used by principal market participants, based on estimated replacement cost, or based on a multiple of operating cash flow validated with historical market transactions of similar assets where possible. The expected future cash flows used for impairment reviews and related fair value calculations are based on estimated future throughputs, tariffs and fees, operating costs and capital project decisions, considering all available evidence at the date of review. Impairment of Investments in Nonconsolidated Entities Investments in nonconsolidated entities are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value has occurred. When indicators exist, the fair value is estimated and compared to the investment carrying value. If any impairment is judgmentally determined to be other than temporary, the carrying value of the investment is written down to fair value. The fair value of the impaired investment is determined based on quoted market prices, if available, or upon the present value of expected future cash flows using discount rates and other assumptions believed to be consistent with those used by principal market participants and a market analysis of comparable assets, if appropriate. Goodwill Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Goodwill is not amortized, but rather is assessed for impairment annually and when events or changes in circumstances indicate that the fair value of the reporting unit with goodwill has been reduced below carrying value. The majority of our goodwill is related to acquisitions from Phillips 66. In these common control transactions, the net assets acquired are recorded at Phillips 66’s historical carrying value, including any associated goodwill. We have one reporting unit for our goodwill impairment assessment. Asset Retirement Obligations and Environmental Costs Fair values of legal obligations to abandon or remove long-lived assets are recorded in the period in which the obligation arises. When the liability is initially recorded, we capitalize this cost by increasing the carrying amount of the related PP&E. Over time, the liability is increased for the change in its present value, and the capitalized cost in PP&E is depreciated over the useful life of the related asset. Our estimate may change after initial recognition of the obligation, in which case we record an adjustment to the liability and PP&E. Environmental expenditures are expensed or capitalized, depending upon their future economic benefit. Expenditures relating to an existing condition caused by past operations, and those having no future economic benefit, are expensed. Liabilities for environmental expenditures are recorded on an undiscounted basis (unless acquired in a business combination) when environmental assessments or cleanups are probable and the costs can be reasonably estimated. Income Taxes We follow the asset and liability method of accounting for income taxes. Under this method, deferred income taxes are recognized for the tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of our assets and liabilities. Our operations are treated as a partnership for federal and state income tax purposes, with each partner being separately taxed on its share of taxable income. Therefore, we have excluded income taxes from these consolidated financial statements, except for the income tax provision resulting from state laws that apply to entities organized as partnerships. Our tax provision is computed as if we were a stand-alone tax paying entity. Any interest and penalties related to income taxes would be reported in interest and debt expense and operating and maintenance expenses, respectively, in our consolidated statement of income.

Operating Revenues

Operating Revenues	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Operating Revenues	Note 3—Operating Revenues Operating revenues are primarily generated from long-term pipeline transportation, terminaling, storage, processing and fractionation lease and service agreements, mainly with Phillips 66. These agreements typically include escalation clauses to adjust transportation tariffs and terminaling and storage fees to reflect changes in price indices. In addition, most of these agreements contain renewal options, which typically require the mutual consent of both our customers and us. Total operating revenues disaggregated by asset type were as follows: Millions of Dollars 2020 2019 2018 Pipelines $ 436 473 454 Terminals 153 167 157 Storage, processing and other revenues 449 486 434 Total operating revenues $ 1,038 1,126 1,045 The majority of our agreements with Phillips 66 are considered operating leases under GAAP. The classification of a lease as either an operating or a financing lease requires judgment in assessing the contract’s lease and service components and in determining the asset’s fair value. For reporting periods prior to our adoption of the new lease accounting standard, ASU No. 2016-02, as of January 1, 2019, the lease and service elements included in these contracts were separated with the lease element recognized in accordance with the existing lease accounting standard and service element recognized in accordance with the revenue accounting standard. Effective for periods after January 1, 2019, we elected to account for lease and service elements of contracts classified as leases on a combined basis under the provisions of ASU No. 2016-02, except for leases of processing-type assets, which contain non-ratable fees related to turnaround activity. For these types of leases, we continue to separate the lease and service elements based on relative standalone prices and apply the lease standard to the lease element and the revenue standard to the service element. Total operating revenues disaggregated by lease and service revenues were as follows: Millions of Dollars 2020 2019 Lease revenues $ 875 930 Service revenues 163 196 Total operating revenues $ 1,038 1,126 Accounts Receivable We bill our customers, mainly Phillips 66, under our lease and service contracts generally on a monthly basis. Total accounts receivable by revenue type was as follows: Millions of Dollars 2020 2019 Lease receivables $ 87 87 Service receivables 19 18 Total accounts receivable $ 106 105 Deferred Revenues Our deferred revenues represent payments received from our customers, mainly Phillips 66, in advance of the period in which lease and service contract performance obligations have been fulfilled. The majority of our deferred revenues relate to a tolling agreement and a storage agreement that are classified as leases. The remainder of our deferred revenues relate to lease and service agreements that contain minimum volume commitments with recovery provisions. Our deferred revenues are recorded in the “Deferred revenues” and “Other liabilities” line items on our consolidated balance sheet. Total deferred revenues under our lease and service agreements were as follows: Millions of Dollars 2020 2019 Deferred lease revenues $ 45 41 Deferred service revenues 4 1 Total deferred revenues $ 49 42 Future Minimum Lease Payments from Customers At December 31, 2020, future minimum payments to be received under our lease agreements with customers were estimated to be: Millions 2021 $ 765 2022 752 2023 706 2024 588 2025 530 Remaining years 1,297 Total future minimum lease payments from customers $ 4,638 Remaining Performance Obligations We typically have long-term service contracts with our customers, of which the original durations range from 5 to 15 years. The weighted-average remaining duration of these contracts is 9 years. These contracts include both fixed and variable transaction price components. At December 31, 2020, future service revenues expected to be recognized for the fixed component of the transaction price of our remaining performance obligations from service contracts with our customers that have an original expected duration of greater than one year were: Millions 2021 $ 124 2022 124 2023 124 2024 99 2025 95 Remaining years 381 Total future service revenues $ 947 For the remaining service performance obligations, we applied the exemption for variable prices allocated entirely to a wholly unsatisfied performance obligation or to a wholly unsatisfied promise to transfer distinct services as part of a performance obligation.

Equity Investments

Equity Investments	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	Note 4—Equity Investments The following table summarizes the carrying value of our equity investments: Millions of Dollars Percentage Ownership 2020 2019 Dakota Access, LLC and Energy Transfer Crude Oil Company, LLC (Bakken Pipeline) 25.00 % $ 577 592 Bayou Bridge Pipeline, LLC (Bayou Bridge) 40.00 288 294 DCP Sand Hills Pipeline, LLC (Sand Hills) 33.34 582 595 DCP Southern Hills Pipeline, LLC (Southern Hills) 33.34 217 215 Explorer Pipeline Company (Explorer) 21.94 92 105 Gray Oak Pipeline, LLC 65.00 860 759 Liberty Pipeline LLC (Liberty) 50.00 241 — Paradigm Pipeline LLC (Paradigm) 50.00 141 143 Phillips 66 Partners Terminal LLC (Phillips 66 Partners Terminal) 70.00 15 70 South Texas Gateway Terminal LLC (South Texas Gateway Terminal) 25.00 167 74 STACK Pipeline LLC (STACK) 50.00 64 114 Total equity investments $ 3,244 2,961 Earnings (losses) from our equity investments were as follows: Millions of Dollars 2020 2019 2018 Bakken Pipeline $ 173 226 177 Bayou Bridge 31 31 14 Sand Hills 138 150 119 Southern Hills 42 43 37 Explorer 20 33 43 Gray Oak Pipeline, LLC 68 3 1 Liberty — — — Paradigm 15 14 10 Phillips 66 Partners Terminal (2) 25 28 South Texas Gateway Terminal 5 — — STACK 3 10 10 Total equity in earnings of affiliates $ 493 535 439 Distributions received from our equity affiliates were $677 million, $599 million, and $477 million in 2020, 2019 and 2018, respectively. Dakota Access, LLC (Dakota Access) and Energy Transfer Crude Oil Company, LLC (ETCO) Dakota Access owns a pipeline system that transports crude oil from the Bakken/Three Forks production area in North Dakota to Patoka, Illinois, and ETCO owns a connecting crude oil pipeline system from Patoka to Nederland, Texas. These two pipeline systems collectively form the Bakken Pipeline system, which is operated by a co-venturer. The Bakken Pipeline system went into service in June 2017. We have a positive basis difference of $48 million for this investment, which represents capitalized interest incurred during construction of the pipeline and a capital contribution disbursed to the co-venturer. The positive basis difference is being amortized over periods between 17 and 42 years. In March 2019, a wholly owned subsidiary of Dakota Access closed an offering of $2.5 billion aggregate principal amount of senior unsecured notes, consisting of: • $650 million aggregate principal amount of 3.625% Senior Notes due 2022. • $1.0 billion aggregate principal amount of 3.900% Senior Notes due 2024. • $850 million aggregate principal amount of 4.625% Senior Notes due 2029. Dakota Access and ETCO have guaranteed repayment of the notes. In addition, we and our co-venturers in Dakota Access provided a Contingent Equity Contribution Undertaking (CECU) in conjunction with the notes offering. Under the CECU, the co-venturers may be severally required to make proportionate equity contributions to Dakota Access if there is an unfavorable final judgment in the ongoing litigation related to an easement granted by the U.S. Army Corps of Engineers (USACE) to allow the pipeline to be constructed under Lake Oahe in North Dakota. Contributions may be required if Dakota Access determines that the issues included in any such final judgment cannot be remediated and Dakota Access has or is projected to have insufficient funds to satisfy repayment of the notes. If Dakota Access undertakes remediation to cure issues raised in a final judgment, contributions may be required if any series of the notes become due, whether by acceleration or at maturity, during such time, to the extent Dakota Access has or is projected to have insufficient funds to pay such amounts. At December 31, 2020, our share of the maximum potential equity contributions under the CECU was approximately $631 million. In March 2020, the trial court presiding over this litigation ordered the USACE to prepare an Environmental Impact Statement (EIS) and requested additional information to enable a decision on whether the Dakota Access Pipeline should be shut down while the EIS is being prepared. In July 2020, the trial court ordered the Dakota Access Pipeline to be shut down and emptied of crude oil within 30 days and that the pipeline should remain shut down pending the preparation of the EIS by the USACE, which the USACE has indicated is expected to take approximately 13 months. Dakota Access filed an appeal and a request for a stay of the order, which was granted. In January 2021, the appellate court affirmed the trial court’s order that: (1) vacated Dakota Access’s easement under Lake Oahe, and (2) directed the USACE to prepare an EIS. The appellate court did not affirm the trial court’s order that the Dakota Access Pipeline be shut down and emptied of crude oil. However, the appellate court acknowledged the precise consequences of the vacated easement remain uncertain. Since the pipeline is now an encroachment, the USACE could seek a shutdown of the pipeline during the preparation of the EIS. Alternatively, the trial court could again issue an injunction that the pipeline be shut down, assuming it makes all findings necessary for injunctive relief. A status hearing is scheduled for April 9, 2021, at which time the parties will discuss the appellate court’s decision and how the USACE plans to proceed given the vacating of the easement. If the pipeline is required to cease operations pending the preparation of the EIS, and should Dakota Access and ETCO not have sufficient funds to pay ongoing expenses, we also could be required to support our share of the ongoing expenses, including scheduled interest payments on the notes of approximately $25 million annually, in addition to the potential obligations under the CECU. Gray Oak Pipeline, LLC Gray Oak Pipeline, LLC was formed to develop and construct the Gray Oak Pipeline, which transports crude oil from the Permian and Eagle Ford to Texas Gulf Coast destinations that include Corpus Christi, Texas, and the Sweeny area, including the Phillips 66 Sweeny Refinery. We have a consolidated holding company that owns 65% of Gray Oak Pipeline, LLC. In April 2018, we entered into a Purchase and Sale Agreement with Phillips 66 PDI to acquire its 100% interest in Gray Oak Holdings LLC (Holdings LLC), a limited liability company that, at that time, owned a 100% interest in Gray Oak Pipeline, LLC. We accounted for the acquisition of Holdings LLC as an acquisition of assets under common control. Also in April 2018, a co-venturer acquired a 25% interest in Gray Oak Pipeline, LLC, along with sufficient voting rights over key governance provisions such that we no longer could assert control over Gray Oak Pipeline, LLC. As a result, we (through our consolidated subsidiary Holdings LLC) began using the equity method of accounting for our investment in Gray Oak Pipeline, LLC at that time. I n December 2018, a third party exercised its option to acquire a 35% interest in Holdings LLC. Because Holdings LLC’s sole asset was its 75% ownership interest in Gray Oak Pipeline, LLC, which was considered a financial asset, and because certain restrictions were placed on the third party’s ability to transfer or sell its interest in Holdings LLC during the construction of the Gray Oak Pipeline, the legal sale of the 35% interest did not qualify as a sale under GAAP. Rather, the third party’s subsequent cash contributions to Holdings LLC to fund its share of previously incurred and future construction costs plus a premium to us were reflected as a long-term obligation in the “Obligation from equity interest transfer” line item on our consolidated balance sheet and as financing cash inflows in the “Proceeds from equity interest transfer” line item on our consolidated statement of cash flows. The Gray Oak Pipeline commenced full operations in the second quarter of 2020 and the restrictions placed on the co-venturer were lifted on June 30, 2020, resulting in the recognition of the sale under GAAP. Accordingly, at June 30, 2020, the co-venturer’s 35% interest in the holding company was recharacterized from a long-term obligation to a noncontrolling interest on our consolidated balance sheet, and the premium of $84 million previously paid by the co-venturer in 2019 was recharacterized from a long-term obligation to a gain in our consolidated statement of income. During 2020 and 2019, the co-venturer contributed an aggregate of $61 million and $342 million, respectively, into Holdings LLC, and Holdings LLC used these contributions to fund its portion of Gray Oak Pipeline, LLC’s cash calls. We have an effective ownership interest of 42.25% in Gray Oak Pipeline, LLC, after considering our co-venturer’s 35% interest in the consolidated holding company. In February 2019, Holdings LLC transferred a 10% interest in Gray Oak Pipeline, LLC, to a third party that exercised a purchase option, for proceeds of $81 million. The proceeds received from this sale are reflected as an investing cash inflow in the “proceeds from sale of equity interest” line item on our consolidated statement of cash flows. In June 2019, Gray Oak Pipeline, LLC entered into a third-party term loan facility. We and our co-venturers provided a guarantee through an equity contribution agreement requiring proportionate equity contributions to Gray Oak Pipeline, LLC up to the total outstanding loan amount. The net proceeds from the term loan were used by Gray Oak Pipeline, LLC for construction of the Gray Oak Pipeline and repayment of amounts borrowed under a related party loan agreement that we and our co-venturers executed in March 2019 and terminated upon the repayment by Gray Oak Pipeline, LLC in June 2019. Our total related party loan to and repayment received from Gray Oak Pipeline, LLC was $95 million. In September 2020, Gray Oak Pipeline, LLC closed its offering of $1.4 billion aggregate principal amount of senior unsecured notes with maturities ranging from 2023 to 2027. These senior notes are not guaranteed by the Partnership or any of its co-venturers. Net proceeds from the offering were used to repay the $1,379 million outstanding under the third-party term loan facility described above, and for general company purposes. Concurrent with the full repayment of the third-party term loan facility, the associated guarantee we issued through an equity contribution agreement was terminated. During its development phase, Gray Oak Pipeline, LLC was considered a variable interest entity (VIE) because it did not have sufficient equity at risk to fully fund the construction of all assets required for principal operations. We determined we were not the primary beneficiary because we and our co-venturers jointly directed the activities of Gray Oak Pipeline, LLC that most significantly impact economic performance. The Gray Oak Pipeline commenced full operations in the second quarter of 2020 and ceased being a VIE. Liberty In February 2020, we entered into a Purchase and Sale Agreement with Phillips 66 PDI to acquire its 50% interest in the Liberty Pipeline joint venture for $75 million. The purchase price reflected the reimbursement of project costs incurred by Phillips 66 prior to the effective date of the transaction. The transaction was funded through a combination of cash on hand and our revolving credit facility, and closed on March 2, 2020. Liberty was formed to develop and construct the Liberty Pipeline system which, upon completion, will transport crude oil from the Rockies and Bakken production areas to Cushing, Oklahoma. On March 24, 2020, we and our co-venturer announced we are deferring the development and construction of the Liberty Pipeline system as a result of the challenging business environment . Liberty is considered a VIE because it does not have sufficient equity at risk to fully fund the construction of all assets required for principal operations. We have determined we are not the primary beneficiary because we and our co-venturer jointly direct the activities of Liberty that most significantly impact economic performance. At December 31, 2020, our maximum exposure to loss was $241 million, which represented the aggregate book value of our equity investment in Liberty. Bayou Bridge Bayou Bridge is a joint venture that owns a pipeline that transports crude oil from Nederland, Texas, to St. James, Louisiana. The Bayou Bridge Pipeline is operated by our co-venturer. Sand Hills Sand Hills is a joint venture with DCP Partners that owns an NGL pipeline system that extends from the Permian Basin and Eagle Ford to facilities along the Texas Gulf Coast and the Mont Belvieu, Texas market hub. The Sand Hills Pipeline system is operated by DCP Partners. Southern Hills Southern Hills is a joint venture with DCP Partners that owns an NGL pipeline system that extends from the Midcontinent region to the Mont Belvieu market hub. The Southern Hills Pipeline system is operated by DCP Partners. We have a negative basis difference of $88 million for this investment, which originated when the pipeline, formerly known as Seaway Products, was sold by Phillips 66 to a related party. The negative basis difference represents a deferred gain and is being amortized over 41 years. Explorer Explorer owns and operates a pipeline system that extends from the Texas Gulf Coast to Indiana. The Explorer Pipeline system transports refined petroleum products to more than 70 major cities in 16 U.S. states. We have a positive basis difference of $71 million for this investment, which represents fair value adjustments attributable to ownership increases in the pipeline. The positive basis difference is being amortized over periods between 7 and 15 years. Paradigm Paradigm is a joint venture that owns the Sacagawea pipelines and Keene Terminal in North Dakota. We account for the joint venture under the equity method of accounting due to governance provisions that require supermajority or unanimous voting on all decisions that significantly impact the governance, management and economic performance of the joint venture. Phillips 66 Partners Terminal Phillips 66 Partners Terminal is a joint venture that owns the Palermo Terminal in North Dakota. We account for the joint venture under the equity method of accounting due to governance provisions that require supermajority or unanimous voting on all decisions that significantly impact the governance, management and economic performance of the joint venture. At December 31, 2020, we estimated the fair value of our investment in Phillips 66 Partners Terminal was below our book value, and we concluded the decline in fair value was not temporary, based upon our projections of future crude oil production in the joint venture’s area of operation. As a result, we recorded a $50 million impairment in the fourth quarter of 2020. The impairment is included in the “Impairments” line item on our consolidated statement of income. The fair value of this equity method investment was calculated by weighting the results of different economic scenarios using the income approach. The income approach uses a discounted cash flow model that requires various observable and unobservable inputs, including volumes, rates, expenses and discount rates. This valuation resulted in a Level 3 nonrecurring fair value measurement. South Texas Gateway Terminal In April 2018, we acquired a 25% interest in the South Texas Gateway Terminal under construction by a co-venturer, which connects to the Gray Oak Pipeline in Corpus Christi. The first dock of the marine export terminal began crude oil export operations in July 2020. The second dock commenced crude oil export operations in the fourth quarter of 2020. During its development phase, South Texas Gateway Terminal was considered a VIE because it did not have sufficient equity at risk to fully fund the construction of all assets required for principal operations. We determined we were not the primary beneficiary because we and our co-venturers jointly directed the activities of the terminal that most significantly impact economic performance. South Texas Gateway Terminal commenced primary operations in the fourth quarter of 2020 and ceased being a VIE. STACK STACK is a joint venture that owns and operates a crude storage terminal and a common carrier pipeline that transports crude oil from the Sooner Trend, Anadarko Basin, Canadian and Kingfisher Counties play in northwestern Oklahoma to Cushing, Oklahoma. At December 31, 2020, we estimated the fair value of our investment in STACK was below our book value, and we concluded the decline in fair value was not temporary, based upon our projections of future crude oil production in the joint venture’s area of operation. As a result, we recorded a $46 million impairment in the fourth quarter of 2020. The impairment is included in the “Impairments” line item on our consolidated statement of income. The fair value of this equity method investment was calculated by weighting the results of different economic scenarios using the income approach. The income approach uses a discounted cash flow model that requires various observable and unobservable inputs, including volumes, tariffs, expenses and discount rates. This valuation resulted in a Level 3 nonrecurring fair value measurement. Summarized 100% financial information for all equity investments is presented on a combined basis below: Millions of Dollars 2020 2019 2018 Revenues $ 2,670 2,753 2,294 Income before income taxes 1,583 1,894 1,536 Net income 1,545 1,832 1,518 Current assets 671 642 751 Noncurrent assets 12,884 12,072 9,561 Current liabilities 381 662 3,008 Noncurrent liabilities 4,673 4,322 496 From acquisition date forward.

Net Income Per Limited Partner

Net Income Per Limited Partner Unit	12 Months Ended
	Dec. 31, 2020
Partners' Capital Notes [Abstract]
Net Income Per Limited Partner Unit	Note 5—Net Income Per Limited Partner Unit We calculate net income attributable to the Partnership per limited partner unit by dividing the limited partners’ interest in net income by the weighted-average number of common units outstanding for the period. After considering the period’s cash distributions declared, the remaining undistributed earnings or excess distributions declared over earnings, if any, are allocated to participating securities in accordance with the contractual terms of our partnership agreement and as prescribed under the two-class method for those periods in which we have participating securities. Participating securities included general partner units and associated incentive distribution rights prior to the restructuring transaction effective August 1, 2019. Our preferred units became participating securities effective October 1, 2020. See Note 13—Equity for information on the restructuring transaction and our preferred units. For the diluted net income per limited partner unit calculation, the preferred units are assumed to be converted at the beginning of the period into common limited partner units on a one-for-one basis, and the distribution formula for available cash in our partnership agreement is recalculated, using the original available cash amount increased only for the preferred distributions declared which would not have been paid after conversion. Any potentially dilutive securities are excluded from the diluted earnings per unit computation if the effect of including such securities would be anti-dilutive. Millions of Dollars 2020 2019 2018 Net income attributable to the Partnership $ 791 923 796 Less: General partner’s distributions declared (including IDRs)* — 139 236 Limited partners’ distributions declared on preferred units* 41 37 37 Limited partners’ distributions declared on common units* 799 609 382 Distributions less than (more than) net income attributable to the Partnership $ (49) 138 141 *Distributions declared are attributable to the indicated periods. 2020 Limited Partners’ Common Units Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 799 41 840 Distributions more than net income attributable to the Partnership (49) — (49) Net income attributable to the Partnership (basic) 750 41 791 Dilutive effect of preferred units 41 Net income attributable to the Partnership (diluted) $ 791 Weighted-average units outstanding—basic 228,333,213 Dilutive effect of preferred units 13,819,791 Weighted-average units outstanding—diluted 242,153,004 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 3.29 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 3.27 2019 Limited Partners’ Common Units General Partner (including IDRs) Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 609 139 37 785 Distributions less than net income attributable to the Partnership 137 1 — 138 Net income attributable to the Partnership (basic) 746 140 37 923 Dilutive effect of preferred units (1) 32 Net income attributable to the Partnership (diluted) $ 778 Weighted-average units outstanding—basic 167,655,306 Dilutive effect of preferred units (1) 13,819,791 Weighted-average units outstanding—diluted 181,475,097 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 4.45 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 4.29 (1) The dilutive effect of the preferred units assumes the reallocation of net income attributable to the Partnership to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement. 2018 Limited Partners’ Common Units General Partner (including IDRs) Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 382 236 37 655 Distributions less than net income attributable to the Partnership 137 4 — 141 Net income attributable to the Partnership (basic) 519 240 37 796 Dilutive effect of preferred units (1) 28 Net income attributable to the Partnership (diluted) $ 547 Weighted-average units outstanding—basic 122,768,582 Dilutive effect of preferred units (1) 13,819,791 Weighted-average units outstanding—diluted 136,588,373 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 4.22 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 4.00 (1) The dilutive effect of the preferred units assumes the reallocation of net income attributable to the Partnership to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement. On January 19, 2021, the Board of Directors of our General Partner declared a quarterly cash distribution of $0.875 per common unit, which resulted in a total distribution to common unitholders of $200 million attributable to the fourth quarter of 2020. This distribution was paid February 12, 2021, to common unitholders of record as of January 29, 2021. Beginning with the distribution to preferred unitholders attributable to the fourth quarter of 2020, the preferred unitholders are entitled to receive cumulative quarterly distributions equal to the greater of $0.678375 per unit, or the per-unit distribution amount paid to the common unitholders. Preferred unitholders received $12 million of distributions attributable to the fourth quarter of 2020. This distribution was paid February 12, 2021, to preferred unitholders of record as of January 29, 2021.

Major Customer and Concentratio

Major Customer and Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Major Customer and Concentration of Credit Risk	Note 6—Major Customer and Concentration of Credit Risk Phillips 66 accounted for 98%, 97% and 96% of our total operating revenues for the years ended December 31, 2020, 2019 and 2018, respectively. Through our wholly owned and joint venture operations, we provide crude oil, refined petroleum products and NGL pipeline transportation, terminaling and storage, and crude oil gathering, NGL fractionation, crude oil processing, and rail-unloading services to Phillips 66 and other related parties. We are potentially exposed to concentration of credit risk primarily through our accounts receivable from Phillips 66. These receivables have payment terms of 30 days or less and are settled against any existing payables we may have to Phillips 66 through Phillips 66’s interaffiliate settlement process. We monitor the creditworthiness of Phillips 66, which has an investment grade credit rating.

Properties, Plants and Equipmen

Properties, Plants and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Properties, Plants and Equipment	Note 7—Properties, Plants and Equipment Our investment in PP&E, with the associated accumulated depreciation, at December 31 was: Estimated Useful Lives Millions of Dollars 2020 2019 Land $ 19 19 Buildings and improvements 3 to 30 years 115 94 Pipelines and related assets* 10 to 45 years 1,518 1,424 Terminals and related assets* 25 to 45 years 847 741 Rail racks and related assets* 33 years 137 137 Processing and related assets* 25 years 1,063 1,041 Caverns and related assets* 25 to 45 years 732 585 Construction-in-progress 394 367 Gross PP&E 4,825 4,408 Accumulated depreciation (1,186) (1,059) Net PP&E $ 3,639 3,349 *Assets for which we are the lessor.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Note 8—Goodwill The carrying amount of goodwill was as follows: Millions of Dollars 2020 2019 Beginning balance January 1 $ 185 185 Activity during the year — — Ending balance December 31 $ 185 185

Lease Assets and Liabilities

Lease Assets and Liabilities	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Assets and Liabilities	Note 9—Lease Assets and Liabilities We have agreements with Phillips 66 to lease land underlying or associated with certain of our assets. These agreements are classified as operating leases. Due to the economic infeasibility of canceling these leases, we consider them non-cancellable. Certain leases include escalation clauses for adjusting rental payments to reflect changes in price indices. Our lease agreements do not impose any significant restrictions on distribution payments, asset dispositions or borrowing ability. Effective with our implementation of ASU No. 2016-02, we elected to discount lease obligations using our incremental borrowing rate. For all leases, we elected the practical expedient not to separate service and lease costs. Our right-of way agreements in effect prior to January 1, 2019, were not accounted for as leases as they were not initially determined to be leases at their commencement dates. However, modifications to these agreements or new agreements will be assessed and accounted for accordingly under ASU No. 2016-02. For short-term leases, which are leases that, at the commencement date, have a lease term of 12 months or less and do not include an option to purchase the underlying asset that is reasonably certain to be exercised, we elected to not recognize the ROU asset and corresponding lease liability on our consolidated balance sheet. Operating lease ROU assets are recorded in the “Other assets” line item and lease liabilities are recorded in the “Other current liabilities” and “Other liabilities” line items on our consolidated balance sheet. During the years ended December 31, 2020 and 2019, the total operating lease ROU asset was $44 million. Future minimum lease payments and recorded short- and long-term lease liabilities at December 31, 2020, for operating leases were: Millions 2021 $ 3 2022 3 2023 3 2024 3 2025 3 Remaining years 87 Future minimum lease payments 102 Amount representing interest or discounts (58) Total lease liabilities 44 Short-term lease liabilities (1) Long-term lease liabilities $ 43 Operating lease costs and operating cash outflows for the year ended December 31, 2020 and 2019, were not material. The weighted-average remaining lease term for our operating leases as of December 31, 2020 and 2019, was 34 and 35 years, respectively. The weighted-average discount rate for our operating leases as of December 31, 2020 and 2019, was 5.9%.
Lease Assets and Liabilities	Note 9—Lease Assets and Liabilities We have agreements with Phillips 66 to lease land underlying or associated with certain of our assets. These agreements are classified as operating leases. Due to the economic infeasibility of canceling these leases, we consider them non-cancellable. Certain leases include escalation clauses for adjusting rental payments to reflect changes in price indices. Our lease agreements do not impose any significant restrictions on distribution payments, asset dispositions or borrowing ability. Effective with our implementation of ASU No. 2016-02, we elected to discount lease obligations using our incremental borrowing rate. For all leases, we elected the practical expedient not to separate service and lease costs. Our right-of way agreements in effect prior to January 1, 2019, were not accounted for as leases as they were not initially determined to be leases at their commencement dates. However, modifications to these agreements or new agreements will be assessed and accounted for accordingly under ASU No. 2016-02. For short-term leases, which are leases that, at the commencement date, have a lease term of 12 months or less and do not include an option to purchase the underlying asset that is reasonably certain to be exercised, we elected to not recognize the ROU asset and corresponding lease liability on our consolidated balance sheet. Operating lease ROU assets are recorded in the “Other assets” line item and lease liabilities are recorded in the “Other current liabilities” and “Other liabilities” line items on our consolidated balance sheet. During the years ended December 31, 2020 and 2019, the total operating lease ROU asset was $44 million. Future minimum lease payments and recorded short- and long-term lease liabilities at December 31, 2020, for operating leases were: Millions 2021 $ 3 2022 3 2023 3 2024 3 2025 3 Remaining years 87 Future minimum lease payments 102 Amount representing interest or discounts (58) Total lease liabilities 44 Short-term lease liabilities (1) Long-term lease liabilities $ 43 Operating lease costs and operating cash outflows for the year ended December 31, 2020 and 2019, were not material. The weighted-average remaining lease term for our operating leases as of December 31, 2020 and 2019, was 34 and 35 years, respectively. The weighted-average discount rate for our operating leases as of December 31, 2020 and 2019, was 5.9%.

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Note 10—Debt Debt at December 31 was: Millions of Dollars 2020 2019 2.450% Senior Notes due December 2024 $ 300 300 3.605% Senior Notes due February 2025 500 500 3.550% Senior Notes due October 2026 500 500 3.750% Senior Notes due March 2028 500 500 3.150% Senior Notes due December 2029 600 600 4.680% Senior Notes due February 2045 450 450 4.900% Senior Notes due October 2046 625 625 Tax-exempt bonds due April 2020 and April 2021, at weighted-average rates of 0.360% and 1.850% at December 31, 2020 and 2019, respectively 50 75 Revolving credit facility borrowings due January 2021 at weighted-average rate of 1.397% 415 — Debt at face value 3,940 3,550 Net unamortized discounts and debt issuance costs (31) (34) Total debt 3,909 3,516 Short-term debt (465) (25) Long-term debt $ 3,444 3,491 The fair value of our fixed-rate and floating-rate debt is estimated based on observable market prices and is classified as Level 2 of the fair value hierarchy. The fair value of our fixed-rate debt amounted to $3,752 million and $3,650 million at December 31, 2020 and 2019, respectively. The fair value of our floating-rate debt approximated carrying value of $465 million and $75 million at December 31, 2020 and 2019, respectively. Maturities of borrowings outstanding at December 31, 2020, inclusive of net unamortized discounts and debt issuance costs, for the five-year period ending 2025 were $465 million in 2021, $298 million in 2024 and $498 million in 2025. During the year ended December 31, 2020, our debt at face value increased $390 million due to: • Borrowings of $415 million under the revolving credit facility. • Repayment of a $25 million tranche of the tax-exempt bonds. Revolving Credit Facility Our $750 million revolving credit facility may be used for direct bank borrowings and as support for issuances of letters of credit. We have an option to increase the overall capacity to $1 billion, subject to certain conditions. We also have the option to extend the facility for two additional one-year terms after its July 30, 2024, maturity date, subject to, among other things, the consent of the lenders holding the majority of the commitments and of each lender extending its commitment. The facility is with a broad syndicate of financial institutions and contains covenants that are usual and customary for an agreement of this type, including that, as of the last day of each fiscal quarter, the ratio of total debt to EBITDA for the prior four fiscal quarters must be no greater than 5.0:1.0 (and 5.5:1.0 during the period following certain specified acquisitions). The facility has customary events of default, such as nonpayment of principal when due; nonpayment of interest, fees or other amounts; and violation of covenants. Outstanding revolving borrowings under the facility bear interest, at our option, at either: (a) the Eurodollar rate in effect from time to time plus the applicable margin; or (b) the reference rate (as described in the facility) plus the applicable margin. The facility also provides for customary fees, including commitment fees. The pricing levels for the commitment fees and interest-rate margins are determined based on our credit ratings in effect from time to time. Borrowings under the facility may be short-term or long-term in duration, and we may at any time prepay outstanding borrowings under the facility, in whole or in part, without premium or penalty. At December 31, 2020, borrowings of $415 million were outstanding under this facility, compared with no borrowings outstanding under this facility at December 31, 2019. At both December 31, 2020 and 2019, $1 million in letters of credit had been issued that were supported by this facility. Tax-Exempt Bonds In 2017, we assumed four $25 million tranches of tax-exempt bonds issued by the Brazos River Harbor Navigation District. We repaid one tranche in 2018 and another tranche in April 2020. The two remaining tranches, totaling $50 million, mature in April 2021. The tranches accrue interest monthly based on a daily rate derived by the remarketing agent for the bonds. The interest rates are designed to represent the lowest rate acceptable by the tax-exempt, variable-rate bond market and approximate the tax-exempt bonds trading at par. 2019 Senior Notes On September 6, 2019, we closed on a public offering of $900 million aggregate principal amount of unsecured notes consisting of: • $300 million aggregate principal amount of 2.450% Senior Notes due December 15, 2024. • $600 million aggregate principal amount of 3.150% Senior Notes due December 15, 2029.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Note 11—Contingencies From time to time, lawsuits involving a variety of claims that arise in the ordinary course of business are filed against us. We also may be required to remove or mitigate the effects on the environment of the placement, storage, disposal or release of certain chemical, mineral and petroleum substances at various sites. We regularly assess the need for accounting recognition or disclosure of these contingencies. In the case of all known contingencies (other than those related to income taxes), we accrue a liability when the loss is probable and the amount is reasonably estimable. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. We do not reduce these liabilities for potential insurance or third-party recoveries. If applicable, we accrue receivables for probable insurance or other third-party recoveries. In the case of income-tax-related contingencies, we use a cumulative probability-weighted loss accrual in cases where sustaining a tax position is less than certain. Based on currently available information, we believe it is remote that future costs related to known contingent liability exposures will exceed current accruals by an amount that would have a material adverse impact on our consolidated financial statements. As we learn new facts concerning contingencies, we reassess our position both with respect to accrued liabilities and other potential exposures. Estimates particularly sensitive to future changes include any contingent liabilities recorded for environmental remediation, tax and legal matters. Estimated future environmental remediation costs are subject to change due to such factors as the uncertain magnitude of cleanup costs, the unknown time and extent of such remedial actions that may be required, and the determination of our liability in proportion to that of other potentially responsible parties. Estimated future costs related to tax and legal matters are subject to change as events evolve and as additional information becomes available during the administrative and litigation processes. Environmental We are subject to federal, state and local environmental laws and regulations. We record accruals for contingent environmental liabilities based on management’s best estimates, using all information that is available at the time. We measure estimates and base liabilities on currently available facts, existing technology, and presently enacted laws and regulations, taking into account stakeholder and business considerations. When measuring environmental liabilities, we also consider our prior experience in remediation of contaminated sites, other companies’ cleanup experience, and data released by the U.S. Environmental Protection Agency or other organizations. We consider unasserted claims in our determination of environmental liabilities, and we accrue them in the period they are both probable and reasonably estimable. In the future, we may be involved in additional environmental assessments, cleanups and proceedings. Legal Proceedings Under our amended omnibus agreement, Phillips 66 provides certain services for our benefit, including legal support services, and we pay an operational and administrative support fee for these services. Phillips 66’s legal organization applies its knowledge, experience and professional judgment to the specific characteristics of our cases, employing a litigation management process to manage and monitor the legal proceedings against us. The process facilitates the early evaluation and quantification of potential exposures in individual cases and enables tracking of those cases that have been scheduled for trial and/or mediation. Based on professional judgment and experience in using these litigation management tools and available information about current developments in all our cases, Phillips 66’s legal organization regularly assesses the adequacy of current accruals and determines if adjustment of existing accruals, or establishment of new accruals, is required. At December 31, 2020 and 2019, we did not have any material accrued contingent liabilities associated with litigation matters. Indemnification and Excluded Liabilities Under our amended omnibus agreement and pursuant to the terms of various agreements under which we acquired assets from Phillips 66, Phillips 66 will indemnify us, or assume responsibility, for certain environmental liabilities, tax liabilities, litigation and any other liabilities attributable to the ownership or operation of the assets contributed to us and that arose prior to the effective date of each acquisition. These indemnifications and exclusions from liability have, in some cases, time limits and deductibles. When Phillips 66 performs under any of these indemnifications or exclusions from liability, we recognize noncash expenses and associated noncash capital contributions from our General Partner, as these are considered liabilities paid for by a principal unitholder.

Assets Retirement Obligations a

Assets Retirement Obligations and Accrued Environmental Costs	12 Months Ended
	Dec. 31, 2020
Assets Retirement Obligations and Accrued Environmental Costs [Abstract]
Asset Retirement Obligations and Accrued Environmental Costs	Note 12—Asset Retirement Obligations and Accrued Environmental Costs Asset retirement obligations and accrued environmental costs at December 31 were: Millions of Dollars 2020 2019 Asset retirement obligations $ 11 11 Accrued environmental costs 2 3 Total asset retirement obligations and accrued environmental costs 13 14 Asset retirement obligations and accrued environmental costs due within one year (1) (1) Long-term asset retirement obligations and accrued environmental costs $ 12 13 Asset Retirement Obligations We have asset retirement obligations we are required to perform under law or contract once an asset is permanently taken out of service. These obligations primarily relate to the abandonment or removal of certain pipelines. Most of these obligations are not expected to be paid until many years in the future. During 2020 and 2019, our asset retirement obligations changed as follows: Millions of Dollars 2020 2019 Balance at January 1 $ 11 11 Accretion of discount 1 — New obligations — — Changes in estimates of existing obligations (1) — Balance at December 31 $ 11 11

Equity

Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Equity	Note 13—Equity ATM Programs We have authorized an aggregate of $750 million under three $250 million continuous offerings of common units, or at-the-market (ATM) programs. The first two programs concluded in June 2018 and December 2019, respectively. For the year ended December 31, 2020, on a settlement-date basis, we issued an aggregate of 40,570 common units, generating net proceeds of $2 million. We temporarily suspended issuances under the ATM program in the first quarter of 2020 due to low common unit prices. During the year ended December 31, 2019, on a settlement-date basis, we issued an aggregate of 3,195,521 common units, generating net proceeds of $173 million. Since inception in June 2016 through December 31, 2020, we issued an aggregate of 9,487,055 common units under our ATM programs, and generated net proceeds of $494 million, after broker commissions of $5 million and other costs of $3 million. The net proceeds from sales under the ATM programs are used for general partnership purposes, which may include debt repayment, acquisitions, capital expenditures and additions to working capital. Restructuring Transaction On August 1, 2019, we closed on the transactions contemplated by the Partnership Interests Restructuring Agreement, dated July 24, 2019, entered into with our General Partner. Pursuant to this agreement, all of the outstanding IDRs held by our General Partner were eliminated and its approximately 2% general partner interest in us was converted into a non-economic general partner interest; both in exchange for an aggregate of 101 million common units issued to Phillips 66 PDI. Because these transactions were between entities under common control, the common units issued to Phillips 66 PDI were not assigned any value; rather, our General Partner’s negative equity balance of $1.4 billion at August 1, 2019, was transferred to Phillips 66’s limited partner equity account. Preferred Units The preferred units rank senior to all common units with respect to distributions and rights upon liquidation. The holders of the preferred units were entitled to receive cumulative quarterly distributions equal to $0.678375 per unit, beginning for the quarter ended December 31, 2017, with a prorated amount from the date of issuance. Beginning with the distribution to preferred unitholders attributable to the fourth quarter of 2020, the preferred unitholders are entitled to receive cumulative quarterly distributions equal to the greater of $0.678375 per unit, or the per-unit distribution amount paid to the common unitholders as if such preferred units had converted into common units immediately prior to the record date. The holders of the preferred units may convert their preferred units into common units, on a one-for-one basis, at any time after the second anniversary of the issuance date, in full or in part, subject to minimum conversion amounts and conditions. After the third anniversary of the issuance date, we may convert the preferred units into common units at any time, in whole or in part, subject to certain minimum conversion amounts and conditions, if the arithmetic average of the volume-weighted trading price of our common units is greater than $73.2645 per unit for the 20 day trading period

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Note 14—Related Party Transactions Commercial Agreements We have entered into long-term, fee-based commercial agreements with Phillips 66 to provide transportation, terminaling, storage, stevedoring, fractionation, processing, and rail terminal services. Under these agreements, Phillips 66 commits to provide us with minimum transportation, throughput or storage volumes, or minimum monthly service fees. If Phillips 66 does not meet its minimum volume commitments under an agreement, Phillips 66 pays us a deficiency payment based on the calculation described in the agreement. Amended and Restated Operational Services Agreement Under our amended and restated operational services agreement, we reimburse Phillips 66 for certain operational services provided in support of our pipelines, terminaling, processing, and storage facilities. These services include routine and emergency maintenance and repair services, routine operational activities, routine administrative services, construction and related services and such other services as we and Phillips 66 may mutually agree upon from time to time. Amended Omnibus Agreement The amended omnibus agreement addresses our payment of an operating and administrative support fee and our obligation to reimburse Phillips 66 for all other direct or allocated costs and expenses incurred by Phillips 66 in providing general and administrative services. Additionally, the omnibus agreement addresses Phillips 66’s indemnification to us and our indemnification to Phillips 66 for certain environmental and other liabilities. Further, it addresses the granting of a license from Phillips 66 to us with respect to the use of certain Phillips 66 trademarks. The operational and administrative support fee is for the provision of certain services, including: logistical services; asset oversight, such as operational management and supervision; corporate engineering services, including asset integrity and regulatory services; business development services; executive services; financial and administrative services (including treasury and accounting); information technology; legal services; corporate health, safety and environmental services; facility services; human resources services; procurement services; investor relations; tax matters; and public company reporting services. We pay Phillips 66 an operational and administrative support fee under the terms of our amended omnibus agreement in the amount of $8 million per month. We also reimburse Phillips 66 for all other direct or allocated costs incurred on behalf of us, pursuant to the terms of our amended omnibus agreement. The classification of these charges between operating and maintenance expenses and general and administrative expenses is based on the functional nature of the services performed for our operations. Under our amended and restated operational services agreement, we reimburse Phillips 66 for the provision of certain operational services in support of our operating assets. Additionally, we pay Phillips 66 for insurance services provided to us, and recoveries under these policies are recorded as an offset to our expenses. Operating and maintenance expenses also include volumetric gains and losses associated with volumes transported by Phillips 66. Tax Sharing Agreement Under our tax sharing agreement, we reimburse Phillips 66 for our share of state and local income and other taxes incurred by Phillips 66 due to our results of operations being included in a combined or consolidated tax return filed by Phillips 66. Any reimbursement is limited to the tax that we (and our subsidiaries) would have paid had we not been included in a combined group with Phillips 66. Phillips 66 may use its tax attributes to cause its combined or consolidated group to owe no tax; however, we would nevertheless reimburse Phillips 66 for the tax we would have owed, even though Phillips 66 had no cash expense for that period. Related Party Transactions Significant related party transactions included in our costs and expenses were: Millions of Dollars 2020 2019 2018 Operating and maintenance expenses $ 184 258 214 General and administrative expenses 62 65 60 Other related party balances were included in the following line items on our consolidated balance sheet, all of which were related to commercial agreements with Phillips 66: Millions of Dollars 2020 2019 Prepaid expenses and other current assets $ 7 7 Other assets 47 44 Deferred revenues 27 16 Other current liabilities 1 1 Other liabilities 64 70 Equity Affiliate Arrangements In March 2019, we and our co-venturers in Dakota Access provided a CECU in conjunction with a senior unsecured notes offering. See Note 4—Equity Investments, for additional information. In September 2020, concurrent with the full repayment of a third-party term loan facility by Gray Oak Pipeline, LLC, the associated guarantee we issued through an equity contribution agreement was terminated. See Note 4—Equity Investments, for additional information.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plans	Note 15—Employee Benefit Plans Pension and Retirement Savings Plans Neither we nor our subsidiaries have any employees. Our General Partner has the sole responsibility for providing the employees and other personnel necessary to conduct our operations. All of the employees that conduct our wholly owned businesses are employed by Phillips 66. Those employees participate in benefit plans sponsored by Phillips 66. Most employees of Phillips 66 who provide direct support to our operations do so under the provisions of the amended and restated operational services agreement, which fees include a burden for benefit costs.

Unit-Based Compensation

Unit-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Unit-Based Compensation	Note 16—Unit-Based Compensation In 2013, the Board of Directors of our General Partner adopted the Phillips 66 Partners LP 2013 Incentive Compensation Plan (the ICP). Awards under the ICP are available for officers, directors and employees of our General Partner or its affiliates, and any consultants or other individuals who perform services for the Partnership. The ICP allows for the grant of unit awards, restricted units, phantom units, unit options, unit appreciation rights, distribution equivalent rights, profits interest units and other unit-based awards. The ICP limits the number of common units that may be delivered pursuant to awards to 2,500,000, subject to proportionate adjustment in the event of unit splits and similar events.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 17—Income Taxes We are not a taxable entity for U.S. federal income tax purposes or for the majority of states that impose an income tax. Taxes on our net income are borne generally by our limited partners through the allocation of taxable income. Our income tax provision results from state laws that apply to entities organized as partnerships. For us, this is primarily the state of Texas. At December 31, 2020 and 2019, we had a net deferred tax liability of $10 million and $9 million, respectively. The net deferred tax liability was primarily associated with PP&E and equity investments. Our effective tax rate was less than 1% for the years ended December 31, 2020, 2019 and 2018.

Cash Flow Information

Cash Flow Information	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Information [Abstract]
Cash Flow Information	Note 18—Cash Flow Information Capital Expenditures and Investments Our capital expenditures and investments consisted of: Millions of Dollars 2020 2019 2018 Cash capital expenditures and investments $ 910 1,095 738 Change in capital expenditure accruals 5 (13) 38 Total capital expenditures and investments $ 915 1,082 776 Millions of Dollars 2020 2019 2018 Cash Payments Interest and debt expense $ 124 100 109

Other Financial Information

Other Financial Information	12 Months Ended
	Dec. 31, 2020
Other Income and Expenses [Abstract]
Other Financial Information	Note 19—Other Financial Information Millions of Dollars 2020 2019 2018 Interest and Debt Expense Incurred Debt $ 138 133 119 Other 4 3 3 142 136 122 Capitalized (21) (28) (7) Expensed $ 121 108 115 Other Income Interest income $ 1 3 1 Other 2 3 1 Total other income $ 3 6 2

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Selected Quarterly Financial Information [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) Millions of Dollars Per Common Unit Total Income Net Income Limited Partners’ Net Income Attributable to the Partnership Basic Diluted 2020 First $ 404 227 226 216 0.95 0.93 Second 430 255 255 246 1.07 1.05 Third 394 217 206 196 0.86 0.85 Fourth 390 112 104 92 0.40 0.40 2019 First $ 423 199 198 119 0.96 0.92 Second 401 234 233 153 1.23 1.15 Third 411 238 237 228 1.18 1.15 Fourth 432 255 255 246 1.08 1.06

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (GAAP).
Consolidation Principles and Investments in Affiliates	Consolidation Principles and Investments in Affiliates Our consolidated financial statements include the accounts of majority-owned, controlled subsidiaries. The equity method is used to account for investments in affiliates in which we have the ability to exert significant influence over the affiliates’ operating and financial policies, including any variable interest entities of which we are not the primary beneficiary. Undivided interests in pipelines are consolidated on a proportionate basis.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and the disclosure of contingent assets and liabilities. Actual results could differ from these estimates.
Common Control Transactions	Common Control Transactions Businesses acquired from Phillips 66 and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with ours at their carrying value. Any difference between carrying value and recognized consideration is treated as a capital transaction. Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows.
Revenue Recognition	Revenue Recognition Revenues are primarily recognized for pipeline transportation, terminaling, storage, processing and fractionation services generated under long-term agreements. A significant portion of our revenues are derived from Phillips 66. The majority of these agreements with Phillips 66 are considered operating leases under GAAP. Effective for periods after January 1, 2019, we elected to account for lease and service elements of contracts classified as leases on a combined basis under the provisions of Financial Accounting Standards Board (FASB) Accounting Standards Update (ASU) No. 2016-02, “Leases (Topic 842),” except for leases of processing-type assets, which contain non-ratable fees related to turnaround activity. For these types of leases, we continued to separate the lease and service elements based on relative standalone prices and applied the new lease standard to the lease element and the revenue standard to the service element. For new or modified leases, our determination of lease classification involves estimates, primarily related to the fair value of the leased asset based on comparable replacement cost and obsolescence estimates, and the allocation of contract consideration between the lease and non-lease components based on the relative stand-alone selling price. Revenues from fixed minimum volume commitments are recognized over the performance obligation period for stand-ready service contracts. Revenues from the variable element of these stand-ready contracts and other contracts without fixed elements are recognized based on the actual volumes transported, stored, processed and fractionated at contractual rates because the actual volumes specifically relate to our efforts to transfer the distinct services. Generally, our services are billed and payments are received on a monthly basis. Billings to Phillips 66 for shortfall volumes under its quarterly minimum volume commitments are recorded as “Deferred revenues” in our consolidated balance sheet, as Phillips 66 generally has the right to make up the shortfall volumes in the following four quarters. For the lease element of the contracts, the deferred revenue will be recognized at the earlier of when shortfall volumes are made up, when the make-up rights contractually expire or when we determine the system will not have the necessary capacity to enable a customer to make up the shortfall volumes. For the service element of the contracts, the deferred revenue will be recognized when the performance obligation is complete or it is probable that the shortfall volumes will not be made up. Billings for tolling services relating to maintenance turnaround activities are billed in advance of such activities. These billings are initially recorded as “Deferred revenues” in our consolidated balance sheet and are recognized when the maintenance turnaround activity commences. Deferred revenue relating to maintenance turnaround operating expenses is recognized in the period the work is performed. Deferred revenue relating to capital projects performed concurrently with a maintenance turnaround is recognized ratably over the remaining tolling services agreement once the equipment is placed into service.
Cash Equivalents	Cash Equivalents Cash equivalents are highly liquid, short-term investments that are readily convertible to known amounts of cash and will mature within 90 days or less from the date of acquisition. We carry these at cost plus accrued interest, which approximates fair value.
Imbalances	Imbalances We do not purchase or produce crude oil, refined petroleum or NGL product inventories. We experience imbalances as a result of variances in meter readings and in other measurement methods, and volume fluctuations within our crude oil, refined petroleum products and NGL systems due to pressure and temperature changes. Certain of our transportation contracts provide for the shipper to pay a contractual loss allowance, which is valued using quoted market prices of the applicable commodity being shipped. These contractual loss allowances, which are received from the shipper irrespective of, and independently calculated from, actual volumetric gains or losses, are recorded as revenue. Any actual volumetric gains or losses are valued using quoted market prices of the applicable commodities and are recorded as decreases or increases to operating and maintenance expenses, respectively.
Fair Value Measurements	Fair Value Measurements We measure assets and liabilities requiring fair value presentation or disclosure using the price that would be received to sell an asset or paid to transfer a liability (i.e., an exit price), and disclose such amounts according to the quality of valuation inputs under the following hierarchy: Level 1: Quoted prices in an active market for identical assets or liabilities. Level 2: Observable inputs other than quoted prices included within Level 1 for the asset or liability, either directly or indirectly through market-corroborated inputs. Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities. We classify the fair value of an asset or liability based on the lowest level of input significant to its measurement. A fair value initially reported as Level 3 will be subsequently reported as Level 2 if the unobservable inputs become inconsequential to its measurement, or corroborating market data becomes available. Asset and liability fair values initially reported as Level 2 will be subsequently reported as Level 3 if corroborating market data becomes unavailable. The carrying amounts of our trade receivables and payables approximate fair value. Nonrecurring Fair Value Measurements
Properties, Plants and Equipment (PP&E)	Properties, Plants and Equipment (PP&E) PP&E is recorded at cost. Costs of maintenance and repairs, which are not significant improvements, are expensed when incurred. Depreciation of PP&E is determined by the individual-unit-straight-line method or the group-straight-line method (for those individual units that are highly integrated with other units).
Capitalized Interest	Capitalized Interest Interest from external borrowings is capitalized on major projects with an expected construction period of six months or longer. Capitalized interest is added to the cost of the underlying asset’s PP&E or the applicable equity investment and is amortized over the useful life of the asset.
Major Maintenance Activities	Major Maintenance Activities Costs for planned integrity management projects are expensed in the period incurred. These types of costs include inspection services, contractor repair services, materials and supplies, equipment rentals and labor costs.
Impairment of PP&E	Impairment of PP&E PP&E used in operations are assessed for impairment whenever changes in facts and circumstances indicate a possible significant deterioration in the future cash flows expected to be generated by an asset group. If, upon review, the sum of the undiscounted expected future pretax cash flows of an asset group is less than the carrying value of the asset group, including applicable liabilities, then the carrying value is written down to estimated fair value and the write down is reported as an impairment in the period in which the determination is made. Individual assets are grouped for impairment purposes at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets—generally at the pipeline system, terminal, or processing or fractionation system level. Since there usually is a lack of quoted market prices for our long-lived assets, the fair value of potentially impaired assets is typically determined based on the present value of expected future cash flows using discount rates and other assumptions believed to be consistent with those used by principal market participants, based on estimated replacement cost, or based on a multiple of operating cash flow validated with historical market transactions of similar assets where possible.
Impairment of Investments in Nonconsolidated Entities	Impairment of Investments in Nonconsolidated EntitiesInvestments in nonconsolidated entities are assessed for impairment whenever changes in the facts and circumstances indicate a loss in value has occurred. When indicators exist, the fair value is estimated and compared to the investment carrying value. If any impairment is judgmentally determined to be other than temporary, the carrying value of the investment is written down to fair value. The fair value of the impaired investment is determined based on quoted market prices, if available, or upon the present value of expected future cash flows using discount rates and other assumptions believed to be consistent with those used by principal market participants and a market analysis of comparable assets, if appropriate.
Goodwill	Goodwill Goodwill represents the excess of the purchase price over the estimated fair value of the net assets acquired in the acquisition of a business. Goodwill is not amortized, but rather is assessed for impairment annually and when events or changes in circumstances indicate that the fair value of the reporting unit with goodwill has been reduced below carrying value. The majority of our goodwill is related to acquisitions from Phillips 66. In these common control transactions, the net assets acquired are recorded at Phillips 66’s historical carrying value, including any associated goodwill. We have one reporting unit for our goodwill impairment assessment.
Asset Retirement Obligations and Environmental Costs	Asset Retirement Obligations and Environmental Costs Fair values of legal obligations to abandon or remove long-lived assets are recorded in the period in which the obligation arises. When the liability is initially recorded, we capitalize this cost by increasing the carrying amount of the related PP&E. Over time, the liability is increased for the change in its present value, and the capitalized cost in PP&E is depreciated over the useful life of the related asset. Our estimate may change after initial recognition of the obligation, in which case we record an adjustment to the liability and PP&E.
Income Taxes	Income Taxes We follow the asset and liability method of accounting for income taxes. Under this method, deferred income taxes are recognized for the tax consequences of temporary differences between the financial statement carrying amounts and the tax basis of our assets and liabilities. Our operations are treated as a partnership for federal and state income tax purposes, with each partner being separately taxed on its share of taxable income. Therefore, we have excluded income taxes from these consolidated financial statements, except for the income tax provision resulting from state laws that apply to entities organized as partnerships. Our tax provision is computed as if we were a stand-alone tax paying entity. Any interest and penalties related to income taxes would be reported in interest and debt expense and operating and maintenance expenses, respectively, in our consolidated statement of income.
Net Income Per Limited Partner Unit

Operating Revenues (Tables)

Operating Revenues (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	Total operating revenues disaggregated by asset type were as follows: Millions of Dollars 2020 2019 2018 Pipelines $ 436 473 454 Terminals 153 167 157 Storage, processing and other revenues 449 486 434 Total operating revenues $ 1,038 1,126 1,045 Total operating revenues disaggregated by lease and service revenues were as follows: Millions of Dollars 2020 2019 Lease revenues $ 875 930 Service revenues 163 196 Total operating revenues $ 1,038 1,126
Schedule of Accounts Receivable	Total accounts receivable by revenue type was as follows: Millions of Dollars 2020 2019 Lease receivables $ 87 87 Service receivables 19 18 Total accounts receivable $ 106 105
Schedule of Deferred Revenues	Total deferred revenues under our lease and service agreements were as follows: Millions of Dollars 2020 2019 Deferred lease revenues $ 45 41 Deferred service revenues 4 1 Total deferred revenues $ 49 42
Schedule of Future Minimum Payments Receivable	At December 31, 2020, future minimum payments to be received under our lease agreements with customers were estimated to be: Millions 2021 $ 765 2022 752 2023 706 2024 588 2025 530 Remaining years 1,297 Total future minimum lease payments from customers $ 4,638
Schedule of Expected Timing of Satisfaction	At December 31, 2020, future service revenues expected to be recognized for the fixed component of the transaction price of our remaining performance obligations from service contracts with our customers that have an original expected duration of greater than one year were: Millions 2021 $ 124 2022 124 2023 124 2024 99 2025 95 Remaining years 381 Total future service revenues $ 947

Equity Investments (Tables)

Equity Investments (Tables)	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Equity Investments	The following table summarizes the carrying value of our equity investments: Millions of Dollars Percentage Ownership 2020 2019 Dakota Access, LLC and Energy Transfer Crude Oil Company, LLC (Bakken Pipeline) 25.00 % $ 577 592 Bayou Bridge Pipeline, LLC (Bayou Bridge) 40.00 288 294 DCP Sand Hills Pipeline, LLC (Sand Hills) 33.34 582 595 DCP Southern Hills Pipeline, LLC (Southern Hills) 33.34 217 215 Explorer Pipeline Company (Explorer) 21.94 92 105 Gray Oak Pipeline, LLC 65.00 860 759 Liberty Pipeline LLC (Liberty) 50.00 241 — Paradigm Pipeline LLC (Paradigm) 50.00 141 143 Phillips 66 Partners Terminal LLC (Phillips 66 Partners Terminal) 70.00 15 70 South Texas Gateway Terminal LLC (South Texas Gateway Terminal) 25.00 167 74 STACK Pipeline LLC (STACK) 50.00 64 114 Total equity investments $ 3,244 2,961 Earnings (losses) from our equity investments were as follows: Millions of Dollars 2020 2019 2018 Bakken Pipeline $ 173 226 177 Bayou Bridge 31 31 14 Sand Hills 138 150 119 Southern Hills 42 43 37 Explorer 20 33 43 Gray Oak Pipeline, LLC 68 3 1 Liberty — — — Paradigm 15 14 10 Phillips 66 Partners Terminal (2) 25 28 South Texas Gateway Terminal 5 — — STACK 3 10 10 Total equity in earnings of affiliates $ 493 535 439 Summarized 100% financial information for all equity investments is presented on a combined basis below: Millions of Dollars 2020 2019 2018 Revenues $ 2,670 2,753 2,294 Income before income taxes 1,583 1,894 1,536 Net income 1,545 1,832 1,518 Current assets 671 642 751 Noncurrent assets 12,884 12,072 9,561 Current liabilities 381 662 3,008 Noncurrent liabilities 4,673 4,322 496 From acquisition date forward.

Net Income Per Limited Partne_2

Net Income Per Limited Partner Unit (Tables)	12 Months Ended
	Dec. 31, 2020
Partners' Capital Notes [Abstract]
Schedule of Distributions Declared, Partners Interest in Partnership Net Income and Net Income per Unit by Class	Millions of Dollars 2020 2019 2018 Net income attributable to the Partnership $ 791 923 796 Less: General partner’s distributions declared (including IDRs)* — 139 236 Limited partners’ distributions declared on preferred units* 41 37 37 Limited partners’ distributions declared on common units* 799 609 382 Distributions less than (more than) net income attributable to the Partnership $ (49) 138 141 *Distributions declared are attributable to the indicated periods. 2020 Limited Partners’ Common Units Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 799 41 840 Distributions more than net income attributable to the Partnership (49) — (49) Net income attributable to the Partnership (basic) 750 41 791 Dilutive effect of preferred units 41 Net income attributable to the Partnership (diluted) $ 791 Weighted-average units outstanding—basic 228,333,213 Dilutive effect of preferred units 13,819,791 Weighted-average units outstanding—diluted 242,153,004 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 3.29 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 3.27 2019 Limited Partners’ Common Units General Partner (including IDRs) Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 609 139 37 785 Distributions less than net income attributable to the Partnership 137 1 — 138 Net income attributable to the Partnership (basic) 746 140 37 923 Dilutive effect of preferred units (1) 32 Net income attributable to the Partnership (diluted) $ 778 Weighted-average units outstanding—basic 167,655,306 Dilutive effect of preferred units (1) 13,819,791 Weighted-average units outstanding—diluted 181,475,097 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 4.45 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 4.29 (1) The dilutive effect of the preferred units assumes the reallocation of net income attributable to the Partnership to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement. 2018 Limited Partners’ Common Units General Partner (including IDRs) Limited Partners’ Preferred Units Total Net income attributable to the Partnership (millions): Distributions declared $ 382 236 37 655 Distributions less than net income attributable to the Partnership 137 4 — 141 Net income attributable to the Partnership (basic) 519 240 37 796 Dilutive effect of preferred units (1) 28 Net income attributable to the Partnership (diluted) $ 547 Weighted-average units outstanding—basic 122,768,582 Dilutive effect of preferred units (1) 13,819,791 Weighted-average units outstanding—diluted 136,588,373 Net income attributable to the Partnership per limited partner unit—basic (dollars) $ 4.22 Net income attributable to the Partnership per limited partner unit—diluted (dollars) 4.00 (1) The dilutive effect of the preferred units assumes the reallocation of net income attributable to the Partnership to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement.

Properties, Plants and Equipm_2

Properties, Plants and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Our investment in PP&E, with the associated accumulated depreciation, at December 31 was: Estimated Useful Lives Millions of Dollars 2020 2019 Land $ 19 19 Buildings and improvements 3 to 30 years 115 94 Pipelines and related assets* 10 to 45 years 1,518 1,424 Terminals and related assets* 25 to 45 years 847 741 Rail racks and related assets* 33 years 137 137 Processing and related assets* 25 years 1,063 1,041 Caverns and related assets* 25 to 45 years 732 585 Construction-in-progress 394 367 Gross PP&E 4,825 4,408 Accumulated depreciation (1,186) (1,059) Net PP&E $ 3,639 3,349 *Assets for which we are the lessor.

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The carrying amount of goodwill was as follows: Millions of Dollars 2020 2019 Beginning balance January 1 $ 185 185 Activity during the year — — Ending balance December 31 $ 185 185

Lease Assets and Liabilities (T

Lease Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Operating Lease, Liability	Future minimum lease payments and recorded short- and long-term lease liabilities at December 31, 2020, for operating leases were: Millions 2021 $ 3 2022 3 2023 3 2024 3 2025 3 Remaining years 87 Future minimum lease payments 102 Amount representing interest or discounts (58) Total lease liabilities 44 Short-term lease liabilities (1) Long-term lease liabilities $ 43

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Debt	Debt at December 31 was: Millions of Dollars 2020 2019 2.450% Senior Notes due December 2024 $ 300 300 3.605% Senior Notes due February 2025 500 500 3.550% Senior Notes due October 2026 500 500 3.750% Senior Notes due March 2028 500 500 3.150% Senior Notes due December 2029 600 600 4.680% Senior Notes due February 2045 450 450 4.900% Senior Notes due October 2046 625 625 Tax-exempt bonds due April 2020 and April 2021, at weighted-average rates of 0.360% and 1.850% at December 31, 2020 and 2019, respectively 50 75 Revolving credit facility borrowings due January 2021 at weighted-average rate of 1.397% 415 — Debt at face value 3,940 3,550 Net unamortized discounts and debt issuance costs (31) (34) Total debt 3,909 3,516 Short-term debt (465) (25) Long-term debt $ 3,444 3,491

Assets Retirement Obligations_2

Assets Retirement Obligations and Accrued Environmental Costs (Tables)	12 Months Ended
	Dec. 31, 2020
Assets Retirement Obligations and Accrued Environmental Costs [Abstract]
Schedule of Asset Retirement Obligations and Accrual for Environmental Costs	Asset retirement obligations and accrued environmental costs at December 31 were: Millions of Dollars 2020 2019 Asset retirement obligations $ 11 11 Accrued environmental costs 2 3 Total asset retirement obligations and accrued environmental costs 13 14 Asset retirement obligations and accrued environmental costs due within one year (1) (1) Long-term asset retirement obligations and accrued environmental costs $ 12 13
Schedule of Change in Asset Retirement Obligation	During 2020 and 2019, our asset retirement obligations changed as follows: Millions of Dollars 2020 2019 Balance at January 1 $ 11 11 Accretion of discount 1 — New obligations — — Changes in estimates of existing obligations (1) — Balance at December 31 $ 11 11

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Summary of Related Party Charges	Significant related party transactions included in our costs and expenses were: Millions of Dollars 2020 2019 2018 Operating and maintenance expenses $ 184 258 214 General and administrative expenses 62 65 60 Other related party balances were included in the following line items on our consolidated balance sheet, all of which were related to commercial agreements with Phillips 66: Millions of Dollars 2020 2019 Prepaid expenses and other current assets $ 7 7 Other assets 47 44 Deferred revenues 27 16 Other current liabilities 1 1 Other liabilities 64 70

Cash Flow Information (Tables)

Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Information [Abstract]
Summary of Capital Expenditures, Noncash Investing and Financing Activities and Cash Payments	Our capital expenditures and investments consisted of: Millions of Dollars 2020 2019 2018 Cash capital expenditures and investments $ 910 1,095 738 Change in capital expenditure accruals 5 (13) 38 Total capital expenditures and investments $ 915 1,082 776 Millions of Dollars 2020 2019 2018 Cash Payments Interest and debt expense $ 124 100 109

Other Financial Information (Ta

Other Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Other Income and Expenses [Abstract]
Schedule of Other Financial Information	Millions of Dollars 2020 2019 2018 Interest and Debt Expense Incurred Debt $ 138 133 119 Other 4 3 3 142 136 122 Capitalized (21) (28) (7) Expensed $ 121 108 115 Other Income Interest income $ 1 3 1 Other 2 3 1 Total other income $ 3 6 2

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Selected Quarterly Financial Information [Abstract]
Selected Quarterly Financial Data (Unaudited)	Millions of Dollars Per Common Unit Total Income Net Income Limited Partners’ Net Income Attributable to the Partnership Basic Diluted 2020 First $ 404 227 226 216 0.95 0.93 Second 430 255 255 246 1.07 1.05 Third 394 217 206 196 0.86 0.85 Fourth 390 112 104 92 0.40 0.40 2019 First $ 423 199 198 119 0.96 0.92 Second 401 234 233 153 1.23 1.15 Third 411 238 237 228 1.18 1.15 Fourth 432 255 255 246 1.08 1.06

Business and Basis of Present_2

Business and Basis of Presentation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)refinerysegment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Variable Interest Entity [Line Items]
Number of reportable segments | segment	1
Impairments | $	$ 96	$ 0	$ 0
Phillips 66
Variable Interest Entity [Line Items]
Number of refineries most of our assets are connected to | refinery	9

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2020reporting_unit
Accounting Policies [Abstract]
Expected construction period	6 months
Number of reporting units	1

Operating Revenues - Disaggrega

Operating Revenues - Disaggregated Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from External Customer [Line Items]
Revenues	$ 1,038	$ 1,126	$ 1,045
Pipelines
Revenue from External Customer [Line Items]
Revenues	436	473	454
Terminals
Revenue from External Customer [Line Items]
Revenues	153	167	157
Storage, processing and other revenues
Revenue from External Customer [Line Items]
Revenues	$ 449	$ 486	$ 434

Operating Revenues - Operating

Operating Revenues - Operating Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating revenues	$ 1,038	$ 1,126	$ 1,045
Lease revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating revenues	875	930
Deferred service revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating revenues	$ 163	$ 196

Operating Revenues - Accounts R

Operating Revenues - Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Total accounts receivable	$ 106	$ 105
Lease receivables
Revenue from External Customer [Line Items]
Total accounts receivable	87	87
Service receivables
Revenue from External Customer [Line Items]
Total accounts receivable	$ 19	$ 18

Operating Revenues - Deferred R

Operating Revenues - Deferred Revenue (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Total deferred revenues	$ 49	$ 42
Deferred lease revenues
Revenue from External Customer [Line Items]
Total deferred revenues	45	41
Deferred service revenues
Revenue from External Customer [Line Items]
Total deferred revenues	$ 4	$ 1

Operating Revenues - Schedule o

Operating Revenues - Schedule of Future Minimum Operating Lease Income (Details) $ in Millions	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
2021	$ 765
2022	752
2023	706
2024	588
2025	530
Remaining years	1,297
Total future minimum lease payments from customers	$ 4,638

Operating Revenues - Narrative

Operating Revenues - Narrative (Details)	12 Months Ended
	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Customer contracts, average remaining duration	9 years
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Customer contracts, term	5 years
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Customer contracts, term	15 years

Operating Revenues - Remaining

Operating Revenues - Remaining Performance Obligations (Details) $ in Millions	Dec. 31, 2020USD ($)
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 947
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 124
Timing of satisfaction of performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 124
Timing of satisfaction of performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 124
Timing of satisfaction of performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 99
Timing of satisfaction of performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 95
Timing of satisfaction of performance obligation	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue from External Customer [Line Items]
Remaining performance obligation	$ 381
Timing of satisfaction of performance obligation	1 year

Equity Investments - Schedule o

Equity Investments - Schedule of Carrying Value Equity Investments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Apr. 30, 2018
Schedule of Equity Method Investments [Line Items]
Carrying value	$ 3,244	$ 2,961
Dakota Access, LLC and Energy Transfer Crude Oil Company, LLC (Bakken Pipeline)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	25.00%
Carrying value	$ 577	592
Bayou Bridge Pipeline, LLC (Bayou Bridge)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	40.00%
Carrying value	$ 288	294
DCP Sand Hills Pipeline, LLC (Sand Hills)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	33.34%
Carrying value	$ 582	595
DCP Southern Hills Pipeline, LLC (Southern Hills)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	33.34%
Carrying value	$ 217	215
Explorer Pipeline Company (Explorer)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	21.94%
Carrying value	$ 92	105
Gray Oak Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Percentage ownership	65.00%
Carrying value	$ 860	759
Liberty Pipeline LLC (Liberty)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	50.00%
Carrying value	$ 241	0
Paradigm Pipeline LLC (Paradigm)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	50.00%
Carrying value	$ 141	143
Phillips 66 Partners Terminal LLC (Phillips 66 Partners Terminal)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	70.00%
Carrying value	$ 15	70
South Texas Gateway Terminal LLC (South Texas Gateway Terminal)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	25.00%		25.00%
Carrying value	$ 167	74
STACK Pipeline LLC (STACK)
Schedule of Equity Method Investments [Line Items]
Percentage ownership	50.00%
Carrying value	$ 64	$ 114

Equity Investments - Schedule_2

Equity Investments - Schedule of Equity Investment Earnings (Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	$ 493	$ 535	$ 439
Bakken Pipeline
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	173	226	177
Bayou Bridge
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	31	31	14
Sand Hills
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	138	150	119
Southern Hills
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	42	43	37
Explorer
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	20	33	43
Gray Oak Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	68	3	1
Liberty
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	0	0	0
Paradigm
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	15	14	10
Phillips 66 Partners Terminal
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	(2)	25	28
South Texas Gateway Terminal
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	5	0	0
STACK
Schedule of Equity Method Investments [Line Items]
Equity in earnings of affiliates	$ 3	$ 10	$ 10

Equity Investments - Narrative

Equity Investments - Narrative (Details)

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Jul. 31, 2020

Feb. 29, 2020USD ($)

Feb. 28, 2019USD ($)

Dec. 31, 2020USD ($)citystate

Jun. 30, 2020USD ($)

Sep. 30, 2020USD ($)

Dec. 31, 2020USD ($)citypipeline_systemstate

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Sep. 06, 2019USD ($)

Mar. 31, 2019USD ($)

Apr. 30, 2018

Schedule of Equity Method Investments [Line Items]

Distributions received from affiliates

$ 677,000,000

$ 599,000,000

$ 477,000,000

Gain from equity interest transfer

84,000,000

0

0

Proceeds from sale of equity interest

0

81,000,000

0

Repayments of debt

$ 25,000,000

1,286,000,000

$ 575,000,000

Bakken Pipeline

Schedule of Equity Method Investments [Line Items]

Number of pipeline systems | pipeline_system

2

Basis difference positive (negative)

$ 48,000,000

$ 48,000,000

Ownership interest, percentage

25.00%

25.00%

Dakota Access and ETCO

Schedule of Equity Method Investments [Line Items]

Maximum exposure, undiscounted

$ 631,000,000

$ 631,000,000

Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

65.00%

65.00%

Gain from equity interest transfer

$ 84,000,000

Effective ownership interest, percentage

42.25%

42.25%

Liberty Pipeline LLC (Liberty)

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

50.00%

50.00%

VIE, maximum loss exposure

$ 241,000,000

$ 241,000,000

DCP Southern Hills Pipeline, LLC (Southern Hills)

Schedule of Equity Method Investments [Line Items]

Basis difference positive (negative)

$ (88,000,000)

$ (88,000,000)

Amortization period of basis difference, in years

41 years

Ownership interest, percentage

33.34%

33.34%

Explorer

Schedule of Equity Method Investments [Line Items]

Basis difference positive (negative)

$ 71,000,000

$ 71,000,000

Ownership interest, percentage

21.94%

21.94%

Phillips 66 Partners Terminal LLC (Phillips 66 Partners Terminal)

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

70.00%

70.00%

Impairment recorded

$ 50,000,000

South Texas Gateway Terminal LLC (South Texas Gateway Terminal)

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

25.00%

25.00%

25.00%

STACK Pipeline LLC (STACK)

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

50.00%

50.00%

Impairment recorded

$ 46,000,000

Minimum | Bakken Pipeline

Schedule of Equity Method Investments [Line Items]

Amortization period of basis difference, in years

17 years

Minimum | Explorer

Schedule of Equity Method Investments [Line Items]

Amortization period of basis difference, in years

7 years

Maximum | Bakken Pipeline

Schedule of Equity Method Investments [Line Items]

Amortization period of basis difference, in years

42 years

Maximum | Explorer

Schedule of Equity Method Investments [Line Items]

Amortization period of basis difference, in years

15 years

Dakota Access, LLC

Schedule of Equity Method Investments [Line Items]

Environmental impact statement, estimated time to prepare, period

13 months

Litigation, Court Ordered Pipeline Shut Down, Period

30 days

Gray Oak Holdings LLC | Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Ownership interest, percentage

65.00%

Percentage of ownership

75.00%

Third Party | Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Percentage of ownership

10.00%

100.00%

Payments to fund cash calls

$ 61,000,000

342,000,000

Proceeds from sale of equity interest

$ 81,000,000

Third Party | Gray Oak Holdings LLC

Schedule of Equity Method Investments [Line Items]

Percentage of ownership

35.00%

100.00%

Co-Venturer | Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Percentage of ownership

25.00%

Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Repayments of debt

$ 1,379,000,000

Gray Oak Pipeline, LLC | Third Party

Schedule of Equity Method Investments [Line Items]

Proceeds from related party debt

$ 95,000,000

Dakota Access and ETCO

Schedule of Equity Method Investments [Line Items]

Debt instrument, periodic payment, interest

$ 25,000,000

Explorer

Schedule of Equity Method Investments [Line Items]

Number of cities in which entity operates | city

70

70

Number of states in which entity operates | state

16

16

Senior Notes

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 900,000,000

Senior Notes | Dakota Access, LLC

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 2,500,000,000

Senior Notes | Dakota Access, LLC | Senior Notes Due 2022

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 650,000,000

Interest rate, stated percentage

3.625%

Senior Notes | Dakota Access, LLC | Senior Notes Due 2024

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 1,000,000,000

Interest rate, stated percentage

3.90%

Senior Notes | Dakota Access, LLC | Senior Notes Due 2029

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 850,000,000

Interest rate, stated percentage

4.625%

Senior Notes | Gray Oak Pipeline, LLC

Schedule of Equity Method Investments [Line Items]

Debt instrument, face amount

$ 1,400,000,000

Common Control Transaction | Phillips 66 | Phillips 66 PDI | Liberty Pipeline LLC (Liberty)

Schedule of Equity Method Investments [Line Items]

Consideration transferred

$ 75,000,000

Entities under common control, percentage of voting interests received

50.00%

Equity Investments - Summarized

Equity Investments - Summarized Financial Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Revenues									$ 1,038	$ 1,126	$ 1,045
Income Before Income Taxes	$ 112	$ 217	$ 255	$ 227	$ 255	$ 238	$ 234	$ 199	811	926	800
Net income									791	923	796
Current assets	140				414				140	414
Current liabilities	633				199				633	199
Variable Interest Entity, Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Revenues									2,670	2,753	2,294
Income Before Income Taxes									1,583	1,894	1,536
Net income									1,545	1,832	1,518
Current assets	671				642				671	642	751
Noncurrent assets	12,884				12,072				12,884	12,072	9,561
Current liabilities	381				662				381	662	3,008
Noncurrent liabilities	$ 4,673				$ 4,322				$ 4,673	$ 4,322	$ 496

Net Income Per Limited Partne_3

Net Income Per Limited Partner Unit - Narrative (Details) $ / shares in Units, $ in Millions	Feb. 12, 2021USD ($)$ / shares	Jan. 19, 2021USD ($)$ / shares	Dec. 31, 2020$ / shares	Dec. 31, 2019$ / shares	Dec. 31, 2018$ / shares
Net Income per Limited Partner Unit [Line Items]
Common units conversion ratio			1
Quarterly cash distribution declared, per limited partner unit (in usd per share)			$ 3.500	$ 3.400	$ 2.936
Common Units | Cash Distribution | Subsequent Event
Net Income per Limited Partner Unit [Line Items]
Quarterly cash distribution declared, per limited partner unit (in usd per share)		$ 0.875
Quarterly cash distribution paid, per limited partner unit (in usd per share)	$ 0.875
Distribution made to limited partner, cash distributions declared | $		$ 200
Distribution made to limited partner, cash distributions paid | $	$ 200
Preferred Units | Cash Distribution | Subsequent Event
Net Income per Limited Partner Unit [Line Items]
Quarterly cash distribution declared, per limited partner unit (in usd per share)		$ 0.678375
Quarterly cash distribution paid, per limited partner unit (in usd per share)	$ 0.678375
Distribution made to limited partner, cash distributions declared | $		$ 12
Distribution made to limited partner, cash distributions paid | $	$ 12

Net Income Per Limited Partne_4

Net Income Per Limited Partner Unit - Schedule of Net Income By Class of Participating Securities Distributions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Limited Partners' Capital Account [Line Items]
Net income attributable to the Partnership	$ 791	$ 923	$ 796
Less:
Distributions declared	840	785	655
Distributions less than (more than) net income attributable to the Partnership	(49)	138	141
General Partner
Limited Partners' Capital Account [Line Items]
Net income attributable to the Partnership		140	240
Less:
Distributions declared	0	139	236
Distributions less than (more than) net income attributable to the Partnership		1	4
Preferred Unitholders Public | Limited Partner
Limited Partners' Capital Account [Line Items]
Net income attributable to the Partnership	41	37	37
Less:
Distributions declared	41	37	37
Distributions less than (more than) net income attributable to the Partnership	0	0	0
Common Units | Limited Partner
Limited Partners' Capital Account [Line Items]
Net income attributable to the Partnership	750	746	519
Less:
Distributions declared	799	609	382
Distributions less than (more than) net income attributable to the Partnership	$ (49)	$ 137	$ 137

Net Income Per Limited Partne_5

Net Income Per Limited Partner Unit - Schedule of Net Income By Class of Participating Securities (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Partners' Capital [Abstract]
Distributions declared									$ 840	$ 785	$ 655
Distributions less than (more than) net income attributable to the Partnership									(49)	138	141
Net income attributable to the Partnership									$ 791	923	796
Net income attributable to the Partnership per limited partner unit—basic (in usd per share)	$ 0.40	$ 0.86	$ 1.07	$ 0.95	$ 1.08	$ 1.18	$ 1.23	$ 0.96
Net income attributable to the Partnership per limited partner unit—diluted (in usd per share)	$ 0.40	$ 0.85	$ 1.05	$ 0.93	$ 1.06	$ 1.15	$ 1.15	$ 0.92
Common Units
Partners' Capital [Abstract]
Net income attributable to the Partnership (diluted)										$ 778	$ 547
Weighted-average units outstanding—basic (in shares)									228,333,213	167,655,306	122,768,582
Dilutive effect of preferred units (in shares)									13,819,791	13,819,791	13,819,791
Weighted-average units outstanding—diluted (in shares)									242,153,004	181,475,097	136,588,373
Net income attributable to the Partnership per limited partner unit—basic (in usd per share)									$ 3.29	$ 4.45	$ 4.22
Net income attributable to the Partnership per limited partner unit—diluted (in usd per share)									$ 3.27	$ 4.29	$ 4
Limited Partner
Partners' Capital [Abstract]
Dilutive effect of preferred units										$ 32	$ 28
Limited Partner | Common Units
Partners' Capital [Abstract]
Distributions declared									$ 799	609	382
Distributions less than (more than) net income attributable to the Partnership									(49)	137	137
Net income attributable to the Partnership									750	746	519
Dilutive effect of preferred units									41
Net income attributable to the Partnership (diluted)									791
Limited Partner | Preferred Unitholders Public
Partners' Capital [Abstract]
Distributions declared									41	37	37
Distributions less than (more than) net income attributable to the Partnership									0	0	0
Net income attributable to the Partnership									41	37	37
General Partner
Partners' Capital [Abstract]
Distributions declared									$ 0	139	236
Distributions less than (more than) net income attributable to the Partnership										1	4
Net income attributable to the Partnership										$ 140	$ 240

Major Customer and Concentrat_2

Major Customer and Concentration of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Concentration Risk [Line Items]
Payment terms	30 days
Phillips 66 | Customer Concentration Risk | Operating revenues
Concentration Risk [Line Items]
Concentration risk, percentage	98.00%	97.00%	96.00%

Properties, Plants and Equipm_3

Properties, Plants and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 4,825	$ 4,408
Accumulated depreciation	(1,186)	(1,059)
Net PP&E	3,639	3,349
Land
Property, Plant and Equipment [Line Items]
Gross PP&E	19	19
Buildings and improvements
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 115	94
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	3 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	30 years
Pipelines and related assets
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 1,518	1,424
Pipelines and related assets | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	10 years
Pipelines and related assets | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	45 years
Terminals and related assets
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 847	741
Terminals and related assets | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	25 years
Terminals and related assets | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	45 years
Rail racks and related assets
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	33 years
Gross PP&E	$ 137	137
Processing and related assets
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	25 years
Gross PP&E	$ 1,063	1,041
Caverns and related assets
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 732	585
Caverns and related assets | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	25 years
Caverns and related assets | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Lives	45 years
Construction-in-progress
Property, Plant and Equipment [Line Items]
Gross PP&E	$ 394	$ 367

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Beginning balance January 1	$ 185	$ 185
Activity during the year	0	0
Ending balance December 31	$ 185	$ 185

Lease Assets and Liabilities -

Lease Assets and Liabilities - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
ROU asset	$ 44
Weighted average remaining lease term	34 years	35 years
Weighted average discount rate	5.90%

Lease Assets and Liabilities _2

Lease Assets and Liabilities - Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 3
2022	3
2023	3
2024	3
2025	3
Remaining years	87
Future minimum lease payments	102
Amount representing interest or discounts	(58)
Total lease liabilities	$ 44
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Short-term lease liabilities	$ (1)
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Long-term lease liabilities	$ 43

Debt - Summary of Long-Term Deb

Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Sep. 13, 2019	Sep. 06, 2019
Debt Instrument [Line Items]
Debt current	$ 465	$ 25
Debt at face value	3,940	3,550
Net unamortized discounts and debt issuance costs	(31)	(34)
Total debt	3,909	3,516
Short-term debt	(465)	(25)
Long-term debt	3,444	3,491
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility	$ 415	0
Interest rate, stated percentage	1.397%
Tax-exempt bonds due April 2020 and April 2021, at weighted-average rates of 0.360% and 1.850% at December 31, 2020 and 2019, respectively
Debt Instrument [Line Items]
Debt current	$ 50	75
Short-term debt	$ (50)	$ (75)
Interest rate, stated percentage	0.36%	1.85%
Senior Notes
Debt Instrument [Line Items]
Debt current			$ 400
Short-term debt			$ (400)
Senior Notes | 2.450% Senior Notes due December 2024
Debt Instrument [Line Items]
Long-term debt, gross	$ 300	$ 300
Interest rate, stated percentage	2.45%			2.45%
Senior Notes | 3.605% Senior Notes due February 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 500	500
Interest rate, stated percentage	3.605%
Senior Notes | 3.550% Senior Notes due October 2026
Debt Instrument [Line Items]
Long-term debt, gross	$ 500	500
Interest rate, stated percentage	3.55%
Senior Notes | 3.750% Senior Notes due March 2028
Debt Instrument [Line Items]
Long-term debt, gross	$ 500	500
Interest rate, stated percentage	3.75%
Senior Notes | 3.150% Senior Notes due December 2029
Debt Instrument [Line Items]
Long-term debt, gross	$ 600	600
Interest rate, stated percentage	3.15%			3.15%
Senior Notes | 4.680% Senior Notes due February 2045
Debt Instrument [Line Items]
Long-term debt, gross	$ 450	450
Interest rate, stated percentage	4.68%
Senior Notes | 4.900% Senior Notes due October 2046
Debt Instrument [Line Items]
Long-term debt, gross	$ 625	$ 625
Interest rate, stated percentage	4.90%

Debt - Narrative (Details)

Debt - Narrative (Details)	Oct. 15, 2019USD ($)	Sep. 06, 2019USD ($)	Dec. 31, 2020USD ($)trancheagreement	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)tranche	Sep. 13, 2019USD ($)	Dec. 31, 2017USD ($)tranche
Debt Instrument [Line Items]
Borrowings, current			$ 465,000,000	$ 25,000,000
Repayments of principal, 2021			465,000,000
Repayments of principal, 2024			298,000,000
Repayments of principal, 2025			498,000,000
Debt at face value			390,000,000
Repayments of debt			25,000,000	1,286,000,000	$ 575,000,000
Revolving credit facility			415,000,000	0
Letters of credit outstanding			$ 1,000,000	1,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Number or renewals available to extend the term of the credit agreement | agreement			2
Renewal term			1 year
Debt to EBITDA, ratio			5
Debt to EBITDA, acquisitions, ratio			5.5
Interest rate, stated percentage			1.397%
Credit Agreement | Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit agreement borrowing capacity			$ 750,000,000
Maximum borrowing capacity under option			1,000,000,000
Merey Sweeny Tax-Exempt Bonds
Debt Instrument [Line Items]
Repayments of debt			25,000,000
Municipal Bonds
Debt Instrument [Line Items]
Borrowings, current			$ 50,000,000	$ 75,000,000
Interest rate, stated percentage			0.36%	1.85%
Senior Notes
Debt Instrument [Line Items]
Borrowings, current						$ 400,000,000
Senior notes		$ 900,000,000
Proceeds from debt, net of issuance costs		892,000,000
Senior Notes | Two Point Six Four Six Senior Notes Due Two Thousand Twenty
Debt Instrument [Line Items]
Repayments of debt	$ 300,000,000
Interest rate, stated percentage	2.646%
Senior Notes | 2.450% Senior Notes due December 2024
Debt Instrument [Line Items]
Senior notes		$ 300,000,000
Long-term debt, gross			$ 300,000,000	$ 300,000,000
Interest rate, stated percentage		2.45%	2.45%
Senior Notes | 3.150% Senior Notes due December 2029
Debt Instrument [Line Items]
Senior notes		$ 600,000,000
Long-term debt, gross			$ 600,000,000	600,000,000
Interest rate, stated percentage		3.15%	3.15%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings, current			$ 415,000,000
Fair Value, Inputs, Level 2 | Municipal Bonds And Line Of Credits
Debt Instrument [Line Items]
Debt, fair value			465,000,000	75,000,000
Fair Value, Inputs, Level 2 | Senior Notes
Debt Instrument [Line Items]
Debt, fair value			3,752,000,000	$ 3,650,000,000
Bakken Pipeline and MSLP Acquisition | Municipal Bonds
Debt Instrument [Line Items]
Borrowings, current			$ 50,000,000
Number of tranches | tranche			2		1		4
Long-term debt, gross							$ 25,000,000

Assets Retirement Obligations_3

Assets Retirement Obligations and Accrued Environmental Costs - Summary of Asset Retirement Obligations and Accrued Environmental Costs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligations and Accrued Environmental Costs [Abstract]
Asset retirement obligations	$ 11	$ 11	$ 11
Accrued environmental costs	2	3
Total asset retirement obligations and accrued environmental costs	13	14
Asset retirement obligations and accrued environmental costs due within one year	(1)	(1)
Long-term asset retirement obligations and accrued environmental costs	$ 12	$ 13

Assets Retirement Obligations_4

Assets Retirement Obligations and Accrued Environmental Costs - Schedule of Change in Asset Retirement Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at January 1	$ 11	$ 11
Accretion of discount	1	0
New obligations	0	0
Changes in estimates of existing obligations	(1)	0
Balance at December 31	$ 11	$ 11

Equity (Details)

Equity (Details) $ / shares in Units, $ in Millions	Feb. 12, 2021$ / shares	Jan. 19, 2021$ / shares	Aug. 01, 2019USD ($)shares	Dec. 31, 2020USD ($)offering$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018$ / sharesshares	Dec. 31, 2019offering	Dec. 31, 2020USD ($)offering$ / sharesshares
Limited Partners' Capital Account [Line Items]
Number of common units issued in public offering (in shares) | shares				40,570	3,195,521	2,532,096
Cash distribution paid per common unit (in USD per share)				$ 3.500	$ 3.400	$ 2.936
Common units conversion ratio				1
General Partner Interest To Be Converted Into Non-Economic General Partner Interest
Limited Partners' Capital Account [Line Items]
General partner interest, percent			2.00%
Common Units
Limited Partners' Capital Account [Line Items]
Shares, issued (in shares) | shares			101,000,000
General partners equity balance | $			$ 1,400
Common Units | Cash Distribution | Subsequent Event
Limited Partners' Capital Account [Line Items]
Quarterly cash distribution paid, per limited partner unit (in usd per share)	$ 0.875
Cash distribution paid per common unit (in USD per share)		$ 0.875
Preferred Unitholders Public
Limited Partners' Capital Account [Line Items]
Average of the volume-weighted trading price, threshold (in usd per share)				$ 73.2645
Preferred units, convertible, threshold consecutive trading days				20 days
Convertible threshold average trading volume common units (in shares) | shares				100,000
Price per common limited partner unit (in usd per share)				$ 54.27				$ 54.27
Preferred Unitholders Public | Cash Distribution | Subsequent Event
Limited Partners' Capital Account [Line Items]
Quarterly cash distribution paid, per limited partner unit (in usd per share)	$ 0.678375
Cash distribution paid per common unit (in USD per share)		$ 0.678375
At The Market Offering Program
Limited Partners' Capital Account [Line Items]
Total authorized amount | $				$ 750
At The Market Offering Program | Common Units
Limited Partners' Capital Account [Line Items]
Number of continuous offerings | offering				3				3
Equity offering program, authorized amount, per program | $				$ 250
Number of continuous offerings concluded | offering							2
Number of common units issued in public offering (in shares) | shares				40,570	3,195,521			9,487,055
Issuance of common units | $				$ 2	$ 173			$ 494
Brokers commissions | $								5
Other costs | $								$ 3

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Phillips 66 | Amended Omnibus Agreement | Phillips 66
Related Party Transaction [Line Items]
Administrative fees expense by month	$ 8

Related Party Transactions - Su

Related Party Transactions - Summary of Related Party Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Operating and maintenance expenses	$ 184	$ 258	$ 214
General and administrative expenses	$ 62	$ 65	$ 60

Related Party Transactions - Ot

Related Party Transactions - Other Related Party Balances (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Prepaid expenses and other current assets	$ 11	$ 10
Other assets	50	52
Deferred revenues	27	16
Other current liabilities	3	3
Other liabilities	90	94
Phillips 66
Related Party Transaction [Line Items]
Prepaid expenses and other current assets	7	7
Other assets	47	44
Deferred revenues	27	16
Other current liabilities	1	1
Other liabilities	$ 64	$ 70

Unit-Based Compensation (Detail

Unit-Based Compensation (Details) - Phillips 66 Partners LP 2013 Incentive Compensation Plan - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2013
Phantom Units | Non Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of phantom units granted (in shares)	6,092	4,950	4,326
Common Units | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common units that may be delivered under the ICP plan (in shares)				2,500,000

Income Taxes (Details)

Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Deferred tax liability	$ 10,000,000	$ 9,000,000
Effective tax rate, percentage (less than)	1.00%	1.00%	1.00%
Unrecognized tax benefits	$ 0	$ 0
Income tax penalties and interest expense	$ 0	$ 0	$ 0

Cash Flow Information - Summary

Cash Flow Information - Summary of Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital Expenditures and Investments
Cash capital expenditures and investments	$ 910	$ 1,095	$ 738
Change in capital expenditure accruals	5	(13)	38
Total capital expenditures and investments	915	1,082	776
Cash Payments
Interest and debt expense	$ 124	$ 100	$ 109

Other Financial Information (De

Other Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Incurred
Debt	$ 138	$ 133	$ 119
Other	4	3	3
Incurred, Total	142	136	122
Capitalized	(21)	(28)	(7)
Expensed	121	108	115
Other Income
Interest income	1	3	1
Other	2	3	1
Total other income	$ 3	$ 6	$ 2

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Selected Quarterly Financial Information [Abstract]
Total Revenues and Other Income	$ 390	$ 394	$ 430	$ 404	$ 432	$ 411	$ 401	$ 423	$ 1,618	$ 1,667	$ 1,486
Income Before Income Taxes	112	217	255	227	255	238	234	199	811	926	800
Net Income Attributable to the Partnership	104	206	255	226	255	237	233	198
Limited Partners’ Interest in Net Income Attributable to the Partnership	$ 92	$ 196	$ 246	$ 216	$ 246	$ 228	$ 153	$ 119	$ 750	$ 746	$ 519
Net Income Attributable to the Partnership Per Common Unit—Basic (in usd per share)	$ 0.40	$ 0.86	$ 1.07	$ 0.95	$ 1.08	$ 1.18	$ 1.23	$ 0.96
Net Income Attributable to the Partnership Per Common Unit—diluted (in usd per share)	$ 0.40	$ 0.85	$ 1.05	$ 0.93	$ 1.06	$ 1.15	$ 1.15	$ 0.92