Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 17, 2020	Jun. 28, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-16335
Entity Registrant Name	Magellan Midstream Partners, L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	73-1599053
Entity Address, Address Line One	One Williams Center
Entity Address, Address Line Two	P.O. Box 22186
Entity Address, City or Town	Tulsa
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	74121-2186
City Area Code	918
Local Phone Number	574-7000
Title of 12(b) Security	Common Units
Trading Symbol	MMP
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 14,578,539,904
Entity Common Stock, Shares Outstanding (in shares)		227,787,597
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001126975
Current Fiscal Year End Date	--12-31