Annual report pursuant to Section 13 and 15(d)

REVENUE - Disaggregation of Revenue (Details)

v3.10.0.1
REVENUE - Disaggregation of Revenue (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2018
Sep. 30, 2018
Jun. 30, 2018
Mar. 31, 2018
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Disaggregation of Revenue [Line Items]                      
Operating revenue $ 835.3 $ 834.2 $ 876.9 $ 865.7 $ 838.5 $ 834.8 $ 856.7 $ 832.2 $ 3,412.1 $ 3,362.2 $ 3,144.9
Change in operating revenue                 49.9 $ 217.3  
Change in operating revenue, as a percent                   1.00% 7.00%
Canada                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 158.5 $ 148.9 $ 134.3
Total U.S. Information Solutions                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 1,247.3 1,262.7 $ 1,236.5
Change in operating revenue                 (15.4) $ 26.2  
Change in operating revenue, as a percent                   (1.00%) 2.00%
Total U.S. Information Solutions | Online Information Solutions                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 877.5 $ 889.6 $ 879.3
Change in operating revenue                 (12.1) $ 10.3  
Change in operating revenue, as a percent                   (1.00%) 1.00%
Total U.S. Information Solutions | Mortgage Solutions                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 153.6 $ 148.9 $ 142.2
Change in operating revenue                 4.7 $ 6.7  
Change in operating revenue, as a percent                   3.00% 5.00%
Total U.S. Information Solutions | Financial Marketing Services                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 216.2 $ 224.2 $ 215.0
Change in operating revenue                 (8.0) $ 9.2  
Change in operating revenue, as a percent                   (4.00%) 4.00%
International                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 966.2 $ 932.3 $ 803.6
Change in operating revenue                 33.9 $ 128.7  
Change in operating revenue, as a percent                   4.00% 16.00%
International | Asia Pacific                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 325.6 $ 308.9 $ 244.2
Change in operating revenue                 16.7 $ 64.7  
Change in operating revenue, as a percent                   5.00% 26.00%
International | Europe                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 287.3 $ 273.8 $ 253.6
Change in operating revenue                 13.5 $ 20.2  
Change in operating revenue, as a percent                   5.00% 8.00%
International | Latin America                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 206.6 $ 213.6 $ 183.9
Change in operating revenue                 (7.0) $ 29.7  
Change in operating revenue, as a percent                   (3.00%) 16.00%
International | Canada                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 146.7 $ 136.0 $ 121.9
Change in operating revenue                 10.7 $ 14.1  
Change in operating revenue, as a percent                   8.00% 12.00%
Workforce Solutions                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 826.8 $ 764.2 $ 702.2
Change in operating revenue                 62.6 $ 62.0  
Change in operating revenue, as a percent                   8.00% 9.00%
Workforce Solutions | Verification Services                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 567.0 $ 501.5 $ 437.3
Change in operating revenue                 65.5 $ 64.2  
Change in operating revenue, as a percent                   13.00% 15.00%
Workforce Solutions | Employer Services                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 259.8 $ 262.7 $ 264.9
Change in operating revenue                 (2.9) $ (2.2)  
Change in operating revenue, as a percent                   (1.00%) (1.00%)
Global Consumer Solutions                      
Disaggregation of Revenue [Line Items]                      
Operating revenue                 371.8 $ 403.0 $ 402.6
Change in operating revenue                 $ (31.2) $ 0.4  
Change in operating revenue, as a percent                   (8.00%) 0.00%