v3.26.1
Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenue $ 4,860.2 $ 4,519.3 $ 9,370.6 $ 8,609.6
Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 4,860.2 4,519.3 9,370.6 8,609.6
Intercompany Eliminations        
Disaggregation of Revenue [Line Items]        
Revenue (5.0) (9.7) (12.1) (17.3)
Americas | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 1,212.3 1,060.0 2,327.9 2,116.7
Americas | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 1,189.3 1,040.6 2,284.8 2,078.0
Americas | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 23.0 19.4 43.1 38.7
Americas | United States | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 714.3 [1],[2] 674.1 [3] 1,369.2 [4],[5] 1,362.9 [6]
Americas | United States | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 700.0 660.2 1,340.9 1,333.8
Americas | United States | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 14.3 13.9 28.3 29.1
Americas | Other Americas | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 498.0 385.9 958.7 753.8
Americas | Other Americas | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 489.3 380.4 943.9 744.2
Americas | Other Americas | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 8.7 5.5 14.8 9.6
Americas | Staffing and Interim        
Disaggregation of Revenue [Line Items]        
Revenue 1,103.3 956.4 2,117.3 1,914.7
Americas | Staffing and Interim | United States        
Disaggregation of Revenue [Line Items]        
Revenue 640.0 599.6 1,222.9 1,215.7
Americas | Staffing and Interim | Other Americas        
Disaggregation of Revenue [Line Items]        
Revenue 463.3 356.8 894.4 699.0
Americas | Outcome-Based Solutions and Consulting        
Disaggregation of Revenue [Line Items]        
Revenue 20.0 19.5 38.9 36.6
Americas | Outcome-Based Solutions and Consulting | United States        
Disaggregation of Revenue [Line Items]        
Revenue 2.0 3.1 4.1 5.4
Americas | Outcome-Based Solutions and Consulting | Other Americas        
Disaggregation of Revenue [Line Items]        
Revenue 18.0 16.4 34.8 31.2
Americas | Permanent Recruitment        
Disaggregation of Revenue [Line Items]        
Revenue 40.5 35.9 77.3 73.5
Americas | Permanent Recruitment | United States        
Disaggregation of Revenue [Line Items]        
Revenue 28.6 26.3 56.1 55.6
Americas | Permanent Recruitment | Other Americas        
Disaggregation of Revenue [Line Items]        
Revenue 11.9 9.6 21.2 17.9
Americas | Other        
Disaggregation of Revenue [Line Items]        
Revenue 48.5 48.2 94.4 91.9
Americas | Other | United States        
Disaggregation of Revenue [Line Items]        
Revenue 43.7 45.1 86.1 86.2
Americas | Other | Other Americas        
Disaggregation of Revenue [Line Items]        
Revenue 4.8 3.1 8.3 5.7
Southern Europe | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 2,308.7 2,149.3 4,410.0 3,983.3
Southern Europe | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 2,272.0 2,116.0 4,337.7 3,917.4
Southern Europe | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 36.7 33.3 72.3 65.9
Southern Europe | France | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 1,177.6 1,149.3 2,246.2 2,115.0
Southern Europe | France | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 1,167.8 1,139.1 2,226.2 2,094.2
Southern Europe | France | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 9.8 10.2 20.0 20.8
Southern Europe | Italy | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 521.9 475.9 996.6 873.7
Southern Europe | Italy | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 508.9 463.9 970.7 850.5
Southern Europe | Italy | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 13.0 12.0 25.9 23.2
Southern Europe | Other Southern Europe | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 609.2 524.1 1,167.2 994.6
Southern Europe | Other Southern Europe | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 595.3 513.0 1,140.8 972.7
Southern Europe | Other Southern Europe | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 13.9 11.1 26.4 21.9
Southern Europe | Staffing and Interim        
Disaggregation of Revenue [Line Items]        
Revenue 2,058.9 1,914.2 3,919.1 3,526.0
Southern Europe | Staffing and Interim | France        
Disaggregation of Revenue [Line Items]        
Revenue 1,084.3 1,050.5 2,056.3 1,922.1
Southern Europe | Staffing and Interim | Italy        
Disaggregation of Revenue [Line Items]        
Revenue 484.5 441.7 926.3 810.5
Southern Europe | Staffing and Interim | Other Southern Europe        
Disaggregation of Revenue [Line Items]        
Revenue 490.1 422.0 936.5 793.4
Southern Europe | Outcome-Based Solutions and Consulting        
Disaggregation of Revenue [Line Items]        
Revenue 168.1 155.7 334.8 306.9
Southern Europe | Outcome-Based Solutions and Consulting | France        
Disaggregation of Revenue [Line Items]        
Revenue 62.9 65.6 128.4 129.6
Southern Europe | Outcome-Based Solutions and Consulting | Italy        
Disaggregation of Revenue [Line Items]        
Revenue 15.0 12.9 28.8 24.0
Southern Europe | Outcome-Based Solutions and Consulting | Other Southern Europe        
Disaggregation of Revenue [Line Items]        
Revenue 90.2 77.2 177.6 153.3
Southern Europe | Permanent Recruitment        
Disaggregation of Revenue [Line Items]        
Revenue 42.3 38.7 83.1 75.7
Southern Europe | Permanent Recruitment | France        
Disaggregation of Revenue [Line Items]        
Revenue 10.5 11.5 21.4 22.8
Southern Europe | Permanent Recruitment | Italy        
Disaggregation of Revenue [Line Items]        
Revenue 13.8 12.9 27.5 24.9
Southern Europe | Permanent Recruitment | Other Southern Europe        
Disaggregation of Revenue [Line Items]        
Revenue 18.0 14.3 34.2 28.0
Southern Europe | Other        
Disaggregation of Revenue [Line Items]        
Revenue 39.4   73.0 74.7
Southern Europe | Other | France        
Disaggregation of Revenue [Line Items]        
Revenue 19.9 21.7 40.1 40.5
Southern Europe | Other | Italy        
Disaggregation of Revenue [Line Items]        
Revenue 8.6 8.4 14.0 14.3
Southern Europe | Other | Other Southern Europe        
Disaggregation of Revenue [Line Items]        
Revenue 10.9 10.6 18.9 19.9
Northern Europe | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 825.5 794.4 1,615.6 1,525.2
Northern Europe | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 808.3 773.8 1,582.1 1,484.1
Northern Europe | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 17.2 20.6 33.5 41.1
Northern Europe | Staffing and Interim        
Disaggregation of Revenue [Line Items]        
Revenue 714.0 682.9 1,394.6 1,303.9
Northern Europe | Outcome-Based Solutions and Consulting        
Disaggregation of Revenue [Line Items]        
Revenue 60.8 56.9 121.1 115.6
Northern Europe | Permanent Recruitment        
Disaggregation of Revenue [Line Items]        
Revenue 24.6 27.3 48.5 54.0
Northern Europe | Other        
Disaggregation of Revenue [Line Items]        
Revenue 26.1 27.3 51.4 51.7
APME | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 518.7 525.3 1,029.2 1,001.7
APME | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 507.2 513.3 1,008.0 980.1
APME | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 11.5 12.0 21.2 21.6
APME | Staffing and Interim        
Disaggregation of Revenue [Line Items]        
Revenue 438.6 437.5 869.2 833.5
APME | Outcome-Based Solutions and Consulting        
Disaggregation of Revenue [Line Items]        
Revenue 57.4 64.2 116.1 124.7
APME | Permanent Recruitment        
Disaggregation of Revenue [Line Items]        
Revenue 13.2 13.7 24.6 25.0
APME | Other        
Disaggregation of Revenue [Line Items]        
Revenue 9.5 9.9 19.3 18.5
Northern Europe and APME | Reportable subsegments        
Disaggregation of Revenue [Line Items]        
Revenue 4,865.2 4,529.0 9,382.7 8,626.9
Northern Europe and APME | Services transferred over time        
Disaggregation of Revenue [Line Items]        
Revenue 4,776.8 4,443.7 9,212.6 8,459.6
Northern Europe and APME | Services transferred at a point in time        
Disaggregation of Revenue [Line Items]        
Revenue 88.4 85.3 170.1 167.3
Northern Europe and APME | Staffing and Interim        
Disaggregation of Revenue [Line Items]        
Revenue 4,314.8 3,991.0 8,300.2 7,578.1
Northern Europe and APME | Outcome-Based Solutions and Consulting        
Disaggregation of Revenue [Line Items]        
Revenue 306.3 296.3 610.9 583.8
Northern Europe and APME | Permanent Recruitment        
Disaggregation of Revenue [Line Items]        
Revenue 120.6 115.6 233.5 228.2
Northern Europe and APME | Other        
Disaggregation of Revenue [Line Items]        
Revenue $ 123.5 $ 126.1 $ 238.1 $ 236.8
[1] The United States Selling and Administrative Expenses and OUP included a $30.0 gain on the sale of our Jefferson Wells U.S. business.
[2] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $2.7 for the three months ended June 30, 2026.
[3] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $2.6 for the three months ended June 30, 2025.
[4] The United States Selling and Administrative Expenses and OUP included a $30.0 gain on the sale of our Jefferson Wells U.S. business.
[5] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $5.1 for the six months ended June 30, 2026.
[6] The United States revenues above represent revenues from our company-owned branches and franchise fees received from our franchise operations, which were $4.8 for the six months ended June 30, 2025.