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Financial Derivative Instruments - Fair Values by Balance Sheet Location (Details) - USD ($) $ in Millions | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Fuel derivative contracts | Prepaid expenses and other current assets |  |
Derivatives, Fair Value [Line Items] |  |
Gross amounts of recognized assets | $ 0 | $ 22
Cash collateral deposits held from counterparties for fuel contracts | 0 | 4
Fuel derivative contracts | Other assets |  |
Derivatives, Fair Value [Line Items] |  |
Gross amounts of recognized assets | 0 | 108
Cash collateral deposits held from counterparties for fuel contracts | 0 | 18
Fuel derivative contracts | Accounts and other receivables |  |
Derivatives, Fair Value [Line Items] |  |
Receivable from third parties for fuel contracts | 0 | 1
Designated as Hedging Instrument |  |
Derivatives, Fair Value [Line Items] |  |
Gross amounts of recognized assets | 0 | 130
Designated as Hedging Instrument | Fuel derivative contracts | Prepaid expenses and other current assets |  |
Derivatives, Fair Value [Line Items] |  |
Gross amounts of recognized assets | 0 | 22
Designated as Hedging Instrument | Fuel derivative contracts | Other assets |  |
Derivatives, Fair Value [Line Items] |  |
Gross amounts of recognized assets | $ 0 | $ 108

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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Publisher FASB -URI https://asc.fasb.org/1943274/2147480434/815-10-50-7A Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-22 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 21 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-21 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 20 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-20 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 15 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483444/210-20-55-15 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483466/210-20-50-3 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 4D -Subparagraph (c)(2) -SubTopic 20 -Topic 860 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481326/860-20-50-4D + Details
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