v3.10.0.1
Postretirement Benefit Plans - Summary of Changes in Pension Benefit Obligations and Defined-Benefit Pension Plan Assets (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Service cost $ 16 $ 15 $ 17
Interest cost 12 11 14
Fair value of plan assets at end of year 201    
Accumulated Other Comprehensive Income (Loss) [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Total AOCI at beginning of year 113 91  
Net actuarial loss (gain) (16) 9  
Exchange rate differences (3) 13  
Total AOCI at end of year 94 113 91
Projected Benefit Obligation [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Projected benefit obligation at beginning of year 651 564  
Service cost 16 15  
Interest cost 12 11  
Actuarial (gains) and losses (12) 15  
Curtailments and settlements 0 (1)  
Benefits paid (31) (22)  
Exchange rate differences (19) 69  
Projected benefit obligation at end of year 617 651 564
Plan Assets [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Fair value of plan assets at beginning of year 195 172  
Actual return on plan assets 4 8  
Employer contributions 38 18  
Curtailments and settlements 0 (1)  
Benefits paid (31) (21)  
Exchange rate differences (5) 19  
Fair value of plan assets at end of year 201 195 $ 172
Funded Plans with Assets Less than Accumulated Benefit Obligation [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Funded status (416) (456)  
Classification Of Funded Status      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Accrued pension cost within other non-current liabilities (407) (443)  
Accrued pension cost within accrued liabilities (9) (13)  
Funded status (416) (456)  
Accumulated Benefit Obligation [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Accumulated benefit obligations 578 613  
Plans with Assets Less Than Accumulated Benefit Obligation [Member]      
Pension Plans, Postretirement and Other Employee Benefits [Line Items]      
Fair value of plan assets, Funded plans 197 190  
Accumulated benefit obligations, Funded plans 348 375  
Projected benefit obligations, Funded plans 376 401  
Accumulated benefit obligations, Unfunded plans 226 233  
Projected benefit obligations, Unfunded plans $ 236 $ 243