v3.24.2
Revenue - Schedule of Revenue by Geography (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax $ 2,219 $ 2,118 $ 4,514 $ 4,321
Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 2,199 2,096 4,474 4,271
Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 2,199 2,096 4,474 4,271
HWC [Member]        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,266 1,224 2,610 2,520
HWC [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,251 1,206 2,578 2,487
HWC [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,251 1,206 2,578 2,487
R&B [Member]        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 951 886 1,901 1,774
R&B [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 948 883 1,895 1,768
R&B [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 948 883 1,895 1,768
Corporate Segment [Member]        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 2 [1] 8 [1] 3 27
Corporate Segment [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 0 [1] 7 [1] 1 16
North America [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 1,196 1,149 2,342 2,264
North America [Member] | HWC [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 810 792 1,650 1,615
North America [Member] | R&B [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 386 355 692 646
North America [Member] | Corporate Segment [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 0 2 0 3
Europe [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 744 708 1,628 1,532
Europe [Member] | HWC [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 335 315 707 661
Europe [Member] | R&B [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 409 389 920 860
Europe [Member] | Corporate Segment [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 0 4 1 11
International [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 259 239 504 475
International [Member] | HWC [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 106 99 221 211
International [Member] | R&B [Member] | Operating Segments [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax 153 139 283 262
International [Member] | Corporate Segment [Member] | Service        
Disaggregation Of Revenue [Line Items]        
Revenue from Contract with Customer, Excluding Assessed Tax $ 0 $ 1 $ 0 $ 2
[1] Reimbursable expenses and other, as well as Corporate revenue, are excluded from segment revenue, but included in total revenue on the condensed consolidated statements of comprehensive income. Amounts included in Corporate revenue may include eliminations, adjustments to reserves and impacts from hedged revenue transactions.