Partners' Capital and Distributions - Common Equity Repurchase Program (Details) - Common Equity Repurchase Program - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Nov. 30, 2020
Partners Capital and Distribution [Line Items]
Stock repurchase program, authorized amount		$ 500
Repurchase and cancellation of common units under the Common Equity Repurchase Program (in shares)	6,222,748
Total purchase price of common units repurchased	$ 50
Common equity repurchase program, remaining amount	$ 450
Maximum
Partners Capital and Distribution [Line Items]
Stock repurchase program, authorized amount		$ 500

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

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Balance Type:	debit
Period Type:	duration