v3.20.4
Goodwill - Schedule of Changes in Goodwill (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]          
Cost     $ 10,098 $ 10,063 $ 8,971
Accumulated impairment     (114) (114) (114)
Book value $ 9,949 $ 8,857 $ 9,984 $ 9,949 $ 8,857
Goodwill [Roll Forward]          
Beginning balance, book value 9,949 8,857      
Changes in book value:          
Acquisitions 3 1,138      
Transfer to assets held for sale 0 (41)      
Translation differences 32 (5)      
Total changes 35 1,092      
Ending balance, book value $ 9,984 $ 9,949