v2.4.0.8

Segment Disclosures (Schedule Of Business Segment Reporting Information) (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2014 | Jun. 30, 2013 | Jun. 30, 2014 | Jun. 30, 2013
Segment Reporting Information [Line Items] |  |  |  |
Transportation and terminals revenue | $ 353,568 | $ 282,462 | $ 671,205 | $ 509,733
Product sales revenue | 137,657 | 157,922 | 433,720 | 359,633
Affiliate management fee revenue | 5,221 | 3,528 | 10,127 | 6,967
Total revenue | 496,446 | 443,912 | 1,115,052 | 876,333
Operating expenses | 124,874 | 77,415 | 198,371 | 142,596
Cost of product sales | 109,103 | 115,328 | 307,143 | 275,726
Earnings of non-controlled entities | (1,955) | (736) | (2,421) | (2,787)
Operating margin | 264,424 | 251,905 | 611,959 | 460,798
Depreciation, amortization and impairments | 46,897 | 34,186 | 84,408 | 70,518
G&A expenses | 39,309 | 33,262 | 74,244 | 63,318
Operating profit | 178,218 | 184,457 | 453,307 | 326,962
Operating Segments [Member] | Refined Products [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Transportation and terminals revenue | 232,489 | 202,397 | 442,725 | 367,756
Product sales revenue | 136,334 | 156,321 | 430,044 | 355,736
Affiliate management fee revenue | 0 | 0 | 0 | 0
Total revenue | 368,823 | 358,718 | 872,769 | 723,492
Operating expenses | 97,302 | 66,456 | 148,459 | 112,737
Cost of product sales | 108,817 | 114,460 | 306,573 | 272,758
Earnings of non-controlled entities | 0 | 0 | 0 | 0
Operating margin | 162,704 | 177,802 | 417,737 | 337,997
Depreciation, amortization and impairments | 32,083 | 21,224 | 55,255 | 42,577
G&A expenses | 25,374 | 23,292 | 48,393 | 44,494
Operating profit | 105,247 | 133,286 | 314,089 | 250,926
Operating Segments [Member] | Crude Oil Pipeline and Terminals [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Transportation and terminals revenue | 79,556 | 41,158 | 147,459 | 64,386
Product sales revenue | 0 | 0 | 0 | 0
Affiliate management fee revenue | 4,902 | 3,239 | 9,497 | 6,398
Total revenue | 84,458 | 44,397 | 156,956 | 70,784
Operating expenses | 11,867 | 4,027 | 20,925 | 9,134
Cost of product sales | 0 | 0 | 0 | 0
Earnings of non-controlled entities | (888) | (110) | (708) | (1,485)
Operating margin | 73,479 | 40,480 | 136,739 | 63,135
Depreciation, amortization and impairments | 6,725 | 5,104 | 13,188 | 12,573
G&A expenses | 7,697 | 4,915 | 13,691 | 9,042
Operating profit | 59,057 | 30,461 | 109,860 | 41,520
Operating Segments [Member] | Marine Storage [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Transportation and terminals revenue | 41,523 | 38,907 | 81,021 | 77,591
Product sales revenue | 1,323 | 1,601 | 3,676 | 3,897
Affiliate management fee revenue | 319 | 289 | 630 | 569
Total revenue | 43,165 | 40,797 | 85,327 | 82,057
Operating expenses | 16,544 | 7,694 | 30,630 | 22,247
Cost of product sales | 286 | 868 | 570 | 2,968
Earnings of non-controlled entities | (1,067) | (626) | (1,713) | (1,302)
Operating margin | 27,402 | 32,861 | 55,840 | 58,144
Depreciation, amortization and impairments | 7,250 | 7,096 | 14,322 | 13,846
G&A expenses | 6,238 | 5,055 | 12,160 | 9,782
Operating profit | 13,914 | 20,710 | 29,358 | 34,516
Intersegment Eliminations [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Transportation and terminals revenue | 0 | 0 | 0 | 0
Product sales revenue | 0 | 0 | 0 | 0
Affiliate management fee revenue | 0 | 0 | 0 | 0
Total revenue | 0 | 0 | 0 | 0
Operating expenses | (839) | (762) | (1,643) | (1,522)
Cost of product sales | 0 | 0 | 0 | 0
Earnings of non-controlled entities | 0 | 0 | 0 | 0
Operating margin | 839 | 762 | 1,643 | 1,522
Depreciation, amortization and impairments | 839 | 762 | 1,643 | 1,522
G&A expenses | 0 | 0 | 0 | 0
Operating profit | $ 0 | $ 0 | $ 0 | $ 0

X
- Definition Operating margin (loss) + References No definition available. + Details
Name: | mmp_OperatingMarginLoss
Namespace Prefix: | mmp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Total costs incurred and are directly related to energy commodities and services provided during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 2 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(d),(e)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfGoodsAndServicesEnergyCommoditiesAndServices
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate direct operating costs incurred during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_DirectOperatingCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=16385135&loc=d3e33749-111570 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.12) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 + Details
Name: | us-gaap_IncomeLossFromEquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net result for the period of deducting operating expenses from operating revenues. + References No definition available. + Details
Name: | us-gaap_OperatingIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Related Parties -URI http://asc.fasb.org/extlink&oid=16382449 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.1(c)) -URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 07 -Paragraph b -Subparagraph 1 -Article 6 + Details
Name: | us-gaap_RevenueFromRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Revenue from oil and gas-related services including well services (such as drilling, rigs and analytic evaluations), transportation, and other supporting contractor services, during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(d)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_RevenueOilAndGasServices
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Revenue derived from energy-related services such supplying various forms of energy (such as steam, electricity and chilled water from the operation of on-site facilities or cogeneration plants), procurement services provided to energy purchasers, and the marketing and trading of energy commodities and derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
Name: | us-gaap_SalesRevenueFromEnergyCommoditiesAndServices
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration