XML 107 R90.htm IDEA: XBRL DOCUMENT v3.24.0.1
Schedule II - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Allowance for credit losses      
Reserves and allowances deducted from asset accounts      
Balance, beginning of period $ 2 $ 2 $ 2
Additions: charged to cost and expenses   0  
Additions: charged to other accounts   0  
Deductions   0  
Balance, end of period 2 2 2
Allowance for excess materials and supplies      
Reserves and allowances deducted from asset accounts      
Balance, beginning of period 199 183 143
Additions: charged to cost and expenses 6 16 43
Additions: charged to other accounts   0  
Deductions (7) 0 (3)
Balance, end of period 198 199 183
Valuation allowance on deferred tax assets      
Reserves and allowances deducted from asset accounts      
Balance, beginning of period 1,910 1,820 685
Additions: charged to cost and expenses   79 1,167
Additions: charged to other accounts   11  
Deductions (26) 0 (32)
Balance, end of period $ 1,884 $ 1,910 $ 1,820