Fair Value Measurements Fair Value Measurements (Narrative) (Details) (One of DST's unconsolidated affiliates, USD $) In Millions, unless otherwise specified	Sep. 30, 2014 affiliate	Dec. 31, 2013 affiliate
One of DST's unconsolidated affiliates
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Number of unconsolidated affiliates with an interest rate swap	1	1
Interest rate swap liability	$ 47.3	$ 45.5

The fair value as of the balance sheet date of interest rate derivative liabilities reported by an equity method investment of the entity.

No definition available.

Name:	dst_EquityMethodInvestmentSummarizedFinancialInformationInterestRateDerivativeLiabilitiesAtFairValue
Namespace Prefix:	dst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant