Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Refined products	$ 20,449	$ 54,285
Transmix	35,415	28,319
Liquefied petroleum gases	43,442	24,868
Crude oil	13,566	20,839
Additives	6,579	6,067
Total inventory	$ 119,451	$ 134,378

Energy Related Inventory, Transmix

No definition available.

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Namespace Prefix:	mmp_
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- Definition

Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies relating to a source of usable power held for future sale or future use in manufacturing or production process.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of solvents or substances produced by or used in a process to change the shape, form or composition of some related matter.

+ References

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of liquid hydrocarbon components recovered from natural gas.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of petroleum or crude oil.

+ References

+ Details

Name:	us-gaap_EnergyRelatedInventoryPetroleum
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of finished goods inventories for petroleum products, crude oil, petrochemical products, and other oil and gas inventories.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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