XML 505 R25.htm IDEA: XBRL DOCUMENT v3.20.4
Inventories
 12 Months Ended
Dec. 31, 2020
Disclosure Of Inventories [Abstract]  
Inventories
16 Inventories

2020
US$m
2019
US$m
Raw materials and purchased components640 675 
Consumable stores1,050 925 
Work in progress1,288 1,066 
Finished goods and goods for resale1,113 936 
Total inventories
4,091 3,602 
Comprising:
Expected to be used within one year3,917 3,463 
Expected to be used after more than one year174 139 
Total inventories
4,091 3,602 
During 2020, the Group recognised a net inventory write back of US$15 million (2019: net inventory write down of US$42 million). This comprised inventory write-offs of US$35 million (2019: US$134 million) partly offset by write-back of previously written down inventory due to an increase in realisable values amounting to US$50 million (2019: US$92 million).
At 31 December 2020, US$621 million (2019: US$611 million) of inventories were pledged as security for liabilities.