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 |