Financial Derivative Instruments - Fair Values by Balance Sheet Location (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	$ 1,305	$ 696
Gross amounts of recognized liabilities	167	4
Fuel derivative contracts \| Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	922	409
Gross amounts of recognized liabilities	464	80
Fuel derivative contracts \| Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	372	287
Gross amounts of recognized liabilities	162	95
Cash collateral deposits held from counterparties for fuel contracts - current	162	95
Fuel derivative contracts \| Other Current Assets
Derivatives, Fair Value [Line Items]
Cash collateral deposits held from counterparties for fuel contracts - current	297	80
Fuel derivative contracts \| Accounts and other receivables
Derivatives, Fair Value [Line Items]
Receivable from third parties for fuel contracts	125	8
Interest rate derivative contracts \| Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	11	0
Interest rate derivative contracts \| Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of recognized liabilities	0	4
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	1,180	696
Gross amounts of recognized liabilities	0	4
Designated as Hedging Instrument \| Fuel derivative contracts \| Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	797	409
Designated as Hedging Instrument \| Fuel derivative contracts \| Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	372	287
Designated as Hedging Instrument \| Interest rate derivative contracts \| Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	11
Designated as Hedging Instrument \| Interest rate derivative contracts \| Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of recognized liabilities	0	$ 4
Not Designated as Hedging Instrument \| Fuel derivative contracts \| Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of recognized assets	125
Gross amounts of recognized liabilities	$ 167

Derivative, Cash Receivable (Payable) On Hedge

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- Definition

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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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
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- Definition

Fair value, before effects of master netting arrangements, of a financial liability or 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 liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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