Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 24, 2020	Jun. 30, 2019
Document and Entity Information
Document Type	10-K/A
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
Entity File Number	001-34187
Entity Registrant Name	Matson, Inc.
Entity Incorporation, State or Country Code	HI
Entity Tax Identification Number	99-0032630
Entity Address, Address Line One	1411 Sand Island Parkway
Entity Address, City or Town	Honolulu
Entity Address, State or Province	HI
Entity Address, Postal Zip Code	96819
City Area Code	808
Local Phone Number	848-1211
Title of 12(b) Security	Common Stock, without par value
Trading Symbol	MATX
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 Common Stock, Shares Outstanding		43,040,657
Entity Public Float			$ 1,642,293,968
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0000003453
Amendment Flag	false