Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income attributable to DST Systems, Inc.	$ 451.5	$ 427.3	$ 358.2
Other comprehensive loss, net of tax (Note 13):
Available-for-sale securities	(93.2)	10.1	(123.2)
Cash flow hedges	0.2	0.0	0.2
Defined benefit pension	4.1	0.0	0.0
Foreign currency translation	73.7	(35.4)	(22.0)
Other comprehensive loss, net of tax	(15.2)	(25.3)	(145.0)
Comprehensive income	$ 436.3	$ 402.0	$ 213.2