XML 97 R74.htm IDEA: XBRL DOCUMENT v3.20.4
RESERVE ROLLFORWARDS (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance $ 1,047 $ 1,177 $ 1,063
Charges (Credits) to Cost and Expense (69) (100) 132
Charged to Other Accounts 2 (14) 1
Deductions 11 16 19
Ending Balance 969 1,047 1,177
SEC Schedule, 12-09, Allowance, Credit Loss [Member]      
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance 11 11 12
Charges (Credits) to Cost and Expense 4 0 0
Charged to Other Accounts 0 0 0
Deductions 1 0 1
Ending Balance 14 11 11
LIFO Inventory [Member]      
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance 248 337 288
Charges (Credits) to Cost and Expense (22) (89) 44
Charged to Other Accounts 0 0 5
Deductions 0 0 0
Ending Balance 226 248 337
Non-environmental asset retirement obligation Costs [Member]      
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance 48 46 49
Charges (Credits) to Cost and Expense 2 2 (2)
Charged to Other Accounts 1 0 0
Deductions 0 0 1
Ending Balance 51 48 46
Environmental Contingencies [Member]      
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance 287 296 304
Charges (Credits) to Cost and Expense 8 7 9
Charged to Other Accounts 0 0 0
Deductions 10 16 17
Ending Balance 285 287 296
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]      
Movement In Valuation Allowances And Reserves Roll Forward      
Beginning Balance 453 487 410
Charges (Credits) to Cost and Expense (61) (20) 81
Charged to Other Accounts 1 (14) (4)
Deductions 0 0 0
Ending Balance $ 393 $ 453 $ 487