Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions | 3 Months Ended |
Mar. 31, 2022 | Mar. 31, 2021 |
Disaggregation of Revenue [Line Items] | | |
Revenue | $ 5,143.3 | $ 4,924.4 |
Intercompany Eliminations | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 14.5 | |
Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,251.2 | 1,002.9 |
Americas | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,213.8 | 984.9 |
Americas | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 37.4 | 18 |
Americas | United States | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 889.4 | 608.8 |
Americas | United States | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 858.8 | 594.7 |
Americas | United States | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 30.6 | 14.1 |
Americas | Other Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 361.8 | 394.1 |
Americas | Other Americas | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 355 | 390.2 |
Americas | Other Americas | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 6.8 | 3.9 |
Americas | Staffing and Interim | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,076.8 | 885 |
Americas | Staffing and Interim | United States | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 739.9 | 510.1 |
Americas | Staffing and Interim | Other Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 336.9 | 374.9 |
Americas | Outcome-Based Solutions and Consulting | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 69.1 | 38.7 |
Americas | Outcome-Based Solutions and Consulting | United States | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 57.1 | 28.8 |
Americas | Outcome-Based Solutions and Consulting | Other Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 12 | 9.9 |
Americas | Permanent Recruitment | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 65.4 | 34.6 |
Americas | Permanent Recruitment | United States | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 54.2 | 28.5 |
Americas | Permanent Recruitment | Other Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 11.2 | 6.1 |
Americas | Other | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 39.9 | 44.6 |
Americas | Other | United States | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 38.2 | 41.4 |
Americas | Other | Other Americas | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1.7 | 3.2 |
Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 2,193.9 | 2,160.3 |
Southern Europe | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 2,152.7 | 2,129.3 |
Southern Europe | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 41.2 | 31 |
Southern Europe | France | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,192.4 | 1,188.9 |
Southern Europe | France | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,177 | 1,176.9 |
Southern Europe | France | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 15.4 | 12 |
Southern Europe | Italy | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 445 | 402.8 |
Southern Europe | Italy | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 432.4 | 393.5 |
Southern Europe | Italy | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 12.6 | 9.3 |
Southern Europe | Other Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 556.5 | 568.6 |
Southern Europe | Other Southern Europe | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 543.3 | 558.9 |
Southern Europe | Other Southern Europe | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 13.2 | 9.7 |
Southern Europe | Staffing and Interim | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,962.8 | 1,926.3 |
Southern Europe | Staffing and Interim | France | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,101.5 | 1,084 |
Southern Europe | Staffing and Interim | Italy | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 417.8 | 381.5 |
Southern Europe | Staffing and Interim | Other Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 443.5 | 460.8 |
Southern Europe | Outcome-Based Solutions and Consulting | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 172.5 | 186.8 |
Southern Europe | Outcome-Based Solutions and Consulting | France | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 70.3 | 86.5 |
Southern Europe | Outcome-Based Solutions and Consulting | Italy | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 8.1 | 7.7 |
Southern Europe | Outcome-Based Solutions and Consulting | Other Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 94.1 | 92.6 |
Southern Europe | Permanent Recruitment | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 46 | 34.2 |
Southern Europe | Permanent Recruitment | France | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 16.5 | 12.8 |
Southern Europe | Permanent Recruitment | Italy | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 13.7 | 9.7 |
Southern Europe | Permanent Recruitment | Other Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 15.8 | 11.7 |
Southern Europe | Other | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 12.6 | 13 |
Southern Europe | Other | France | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 4.1 | 5.6 |
Southern Europe | Other | Italy | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 5.4 | 3.9 |
Southern Europe | Other | Other Southern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 3.1 | 3.5 |
Northern Europe | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,094.5 | 1,133.8 |
Northern Europe | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 1,057.2 | 1,107.8 |
Northern Europe | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 37.3 | 26 |
Northern Europe | Staffing and Interim | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 977.1 | 1,018.8 |
Northern Europe | Outcome-Based Solutions and Consulting | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 55 | 64.8 |
Northern Europe | Permanent Recruitment | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 45.3 | 29.5 |
Northern Europe | Other | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 17.1 | 20.7 |
APME | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 618.2 | 627.4 |
APME | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 597.1 | 607.9 |
APME | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 21.1 | 19.5 |
APME | Staffing and Interim | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 463.1 | 480.8 |
APME | Outcome-Based Solutions and Consulting | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 109.3 | 98.4 |
APME | Permanent Recruitment | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 37.2 | 37.4 |
APME | Other | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 8.6 | 10.8 |
Northern Europe and APME | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 5,157.8 | 4,924.4 |
Reportable Segments | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 5,157.8 | 4,924.4 |
Reportable Segments | Services transferred over time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 5,020.8 | 4,829.9 |
Reportable Segments | Services transferred at a point in time | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 137 | 94.5 |
Reportable Segments | Staffing and Interim | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 4,479.8 | 4,310.9 |
Reportable Segments | Outcome-Based Solutions and Consulting | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 405.9 | 388.7 |
Reportable Segments | Permanent Recruitment | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | 193.9 | 135.7 |
Reportable Segments | Other | | |
Disaggregation of Revenue [Line Items] | | |
Revenue | $ 78.2 | $ 89.1 |