Available for Sale Investment Maturity Term

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- Definition

Equity Securities, Ownership Percentage

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- Definition

Equity Securities Without Readily Determinable Fair Value, Ownership Interest

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- Definition

Fair Value [Line Items]

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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- Definition

Amount of investment in equity security without readily determinable fair value.

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- Definition

Number of aircraft operated by the carrier.

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- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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Investments and Fair Value Measurements - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) aircraft	Dec. 31, 2019 USD ($)
Fair Value [Line Items]
Unrealized gain (loss) on derivative asset		$ (24)	$ 13
Investments in securities accounted for under the equity method		$ 139
Republic
Fair Value [Line Items]
Number of regional aircraft \| aircraft		66
Champlain
Fair Value [Line Items]
Number of regional aircraft \| aircraft		49
Asset-backed Securities \| Minimum
Fair Value [Line Items]
Available-for-sale securities remaining maturities		1 year
Asset-backed Securities \| Maximum
Fair Value [Line Items]
Available-for-sale securities remaining maturities		14 years
Corporate Debt
Fair Value [Line Items]
Available-for-sale securities remaining maturities		2 years
U.S. Government and Other Securities
Fair Value [Line Items]
Available-for-sale securities remaining maturities		1 year
Azul
Fair Value [Line Items]
Equity stake		2.00%
Gain (loss) on equity securities	$ (136)	$ 180
Carrying value of investment		$ 205
Azul \| Preferred Stock
Fair Value [Line Items]
Equity stake		8.00%
Republic
Fair Value [Line Items]
Ownership stake		19.00%
ManaAir
Fair Value [Line Items]
Ownership stake		49.90%
Champlain
Fair Value [Line Items]
Ownership stake		40.00%
Fulcrum
Fair Value [Line Items]
Ownership interest		0.06
Carrying value of other investment		$ 51
Fulcrum \| Preferred Stock
Fair Value [Line Items]
Ownership interest		0.07
CLEAR
Fair Value [Line Items]
Ownership interest		0.01
Carrying value of other investment		$ 9