v3.19.1
Partners' Capital and Distributions (Narrative) (Details)
$ in Millions
3 Months Ended
Mar. 31, 2019
USD ($)
Partners' Capital [Abstract]
Amount Authorized Under Equity Distribution Agreement
$ 750.0
X
- Definition
Amount Authorized Under Equity Distribution Agreement
+ References
No definition available.
+ Details
Name:
mmp_AmountAuthorizedUnderEquityDistributionAgreement
Namespace Prefix:
mmp_
Data Type:
xbrli:monetaryItemType
Balance Type:
credit
Period Type:
duration
X
- References
No definition available.
+ Details
Name:
us-gaap_PartnersCapitalAbstract
Namespace Prefix:
us-gaap_
Data Type:
xbrli:stringItemType
Balance Type:
na
Period Type:
duration