Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	DST SYSTEMS INC
Entity Central Index Key	0000714603
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 3,746,186,932
Entity Common Stock, Shares Outstanding		59,313,526
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY