v2.4.0.8

Long-Term Incentive Plan (Equity-Based Incentive Compensation Expense) (Details) (Management [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	$ 24,083	$ 21,036	$ 17,710
G&A Expense [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	23,264	18,587	16,024
Operating Expenses [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	819	2,449	1,686
Retention Awards [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	575	693	686
2009 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	0	0	8,682
2010 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	194	8,660	4,662
2011 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	9,639	7,156	3,680
2012 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	7,498	4,527	0
2013 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	6,177	0	0
Liability Method [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	8,551	6,918	6,667
Liability Method [Member] | 2009 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	0	0	4,264
Liability Method [Member] | 2010 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	73	3,723	1,562
Liability Method [Member] | 2011 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	4,280	2,094	841
Liability Method [Member] | 2012 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	2,747	1,101	0
Liability Method [Member] | 2013 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	1,451	0	0
Equity Method [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	15,532	14,118	11,043
Equity Method [Member] | Retention Awards [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	575	693	686
Equity Method [Member] | 2009 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	0	0	4,418
Equity Method [Member] | 2010 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	121	4,937	3,100
Equity Method [Member] | 2011 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	5,359	5,062	2,839
Equity Method [Member] | 2012 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	4,751	3,426	0
Equity Method [Member] | 2013 Awards [Member] | Performance Shares [Member]
Long Term Incentive Plan [Line Items]
Allocation of LTIP expense on Consolidated Statements of Income	$ 4,726	$ 0	$ 0

X

- Details

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Namespace Prefix:	mmp_
Data Type:	xbrli:stringItemType
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X

- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

+ Details

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Balance Type:	debit
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