XML 16 R1.htm IDEA: XBRL DOCUMENT v3.3.1.900
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2015
Feb. 15, 2016
Jun. 30, 2015
Entity Registrant Name FEDERATED INVESTORS INC /PA/    
Entity Central Index Key 0001056288    
Trading Symbol FII    
Document Type 10-K    
Document Period End Date Dec. 31, 2015    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2015    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Amendment Flag false    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Public Float     $ 3,100,000,000
Class A [Member]      
Entity Common Stock, Shares Outstanding   9,000  
Common Class B [Member]      
Entity Common Stock, Shares Outstanding   103,851,327