XML 678 R198.htm IDEA: XBRL DOCUMENT v3.20.4
Financial instruments and risk management - Summary of changes in fair value of Level 3 financial assets and financial liabilities (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]    
Currency translation adjustments $ 890 $ 65
Level 3    
Disclosure of detailed information about financial instruments [line items]    
Opening balance 383 637
Currency translation adjustments 16 (1)
Total realised losses included in consolidated sales revenue 11 0
Total realised losses included in net operating costs (39) (7)
Total unrealised (losses)/gains included in net operating costs 24 (254)
Total unrealised gains transferred into other comprehensive income through cash flow hedges 26 28
Additions 1 1
Disposals/maturity of financial instruments (27) (21)
Closing balance 395 383
Net losses for the year included in the income statement for assets and liabilities held at year end(a) $ 0 $ (263)