Earnings (Loss) Per Share (Computation Of Earnings Per Share) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Loss Per Share [Line Items]
Net Income (Loss)	$ (138)	$ 653	$ 538	$ (213)	$ (325)	$ 387	$ 273	$ (82)	$ 840	$ 253	$ (651)
Less: Income allocable to participating securities									(3)	(1)
Earnings (loss) available to common stockholders									837	252	(651)
Basic weighted-average shares outstanding									329,000,000	207,000,000	151,000,000
Earnings (loss) per share, basic	$ (0.42)	$ 1.97	$ 1.63	$ (0.65)	$ (1.01)	$ 2.30	$ 1.62	$ (0.49)	$ 2.54	$ 1.22	$ (4.32)
Earnings (loss) available to common stockholders									837	252	(651)
Earnings (loss) available to common stockholders including the effect of dilutive securities									864	273	(651)
Effect of employee stock options									2,000,000	2,000,000
Diluted weighted average shares outstanding									383,000,000	253,000,000	151,000,000
Earnings (loss) per share, diluted	$ (0.42)	$ 1.69	$ 1.39	$ (0.65)	$ (1.01)	$ 1.75	$ 1.29	$ (0.49)	$ 2.26	$ 1.08	$ (4.32)
Potentially dilutive shares excluded from diluted per share amounts									21,000,000	35,000,000	73,000,000
Continental 4.5% Convertible Notes [Member]
Earnings Loss Per Share [Line Items]
Effect of convertible notes on diluted earnings per share, amount									9	2
Effect of convertible notes on diluted earnings per share, shares									12,000,000	3,000,000
Debt instrument stated interest rate	4.50%								4.50%
Continental 5% Convertible Notes [Member]
Earnings Loss Per Share [Line Items]
Effect of convertible notes on diluted earnings per share, amount										1
Effect of convertible notes on diluted earnings per share, shares										1,000,000
Debt instrument stated interest rate	5.00%								5.00%
UAL 4.5% Senior Limited Subordination Convertible Notes [Member]
Earnings Loss Per Share [Line Items]
Potentially dilutive shares excluded from diluted per share amounts									11,000,000	22,000,000	22,000,000
Debt instrument stated interest rate	4.50%								4.50%
UAL 5% Senior Convertible Notes [Member]
Earnings Loss Per Share [Line Items]
Potentially dilutive shares excluded from diluted per share amounts										3,000,000	3,000,000
Debt instrument stated interest rate	5.00%								5.00%
Continental 6% Convertible Junior Subordinated Debentures [Member]
Earnings Loss Per Share [Line Items]
Potentially dilutive shares excluded from diluted per share amounts									4,000,000	1,000,000
Debt instrument stated interest rate	6.00%								6.00%
United 6% Senior Convertible Notes [Member]
Earnings Loss Per Share [Line Items]
Effect of convertible notes on diluted earnings per share, amount									$ 18	$ 18
Effect of convertible notes on diluted earnings per share, shares									40,000,000	40,000,000
Potentially dilutive shares excluded from diluted per share amounts											40,000,000
Debt instrument stated interest rate	6.00%								6.00%
Stock Options [Member]
Earnings Loss Per Share [Line Items]
Potentially dilutive shares excluded from diluted per share amounts									5,000,000	9,000,000	7,000,000
Restricted Stock [Member]
Earnings Loss Per Share [Line Items]
Potentially dilutive shares excluded from diluted per share amounts									1,000,000		1,000,000