v3.20.4
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, 2020
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan, Roll Forwards [Abstract]      
Service cost $ 17 $ 14 $ 16
Interest cost 7 12 12
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]      
Fair value of plan assets at end of year 224    
Pension Plan      
Defined Benefit Plan, Roll Forwards [Abstract]      
Projected benefit obligation at beginning of year 665 617  
Service cost 17 14  
Interest cost 7 12  
Actuarial (gains) and losses 65 50  
Curtailments and settlements 0 0  
Benefits paid (22) (23)  
Exchange rate differences 58 (5)  
Projected benefit obligation at end of year 790 665 617
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]      
Defined Benefit Plan, Plan Assets, Amount, Beginning Balance 203 201  
Actual return on plan assets 5 5  
Employer contributions 22 22  
Curtailments and settlements 0 0  
Benefits paid (22) (23)  
Exchange rate differences 16 (2)  
Fair value of plan assets at end of year 224 203 201
Funded status (566) (462)  
Classification of the funded status is as follows      
–   Accrued pension cost within other non-current liabilities (554) (452)  
–   Accrued pension cost within accrued liabilities (12) (10)  
Total (566) (462)  
Accumulated benefit obligation for all Company-dedicated benefit pension plans 755 621  
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]      
Total AOCI at beginning of year 140 94  
Net actuarial loss (gain) 58 47  
Exchange rate differences 16 (1)  
Total AOCI at end of year 214 140 $ 94
Funded Plan | Pension Plan      
Plans with assets less than accumulated benefit obligation (including unfunded plans)      
Fair value of plan assets 220 198  
Accumulated benefit obligations $ 750 $ 617