Statements of Consolidated Stockholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Additional Capital Invested	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	United Airlines, Inc.	United Airlines, Inc. Additional Capital Invested	United Airlines, Inc. Retained Earnings	United Airlines, Inc. Accumulated Other Comprehensive Income (Loss)	United Airlines, Inc. Payable to Parent
Balance at Dec. 31, 2021	$ 5,029	$ 9,156	$ 625	$ (942)	$ 4,998	$ 317	$ 2,977	$ (942)	$ 2,646
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(1,377)		(1,377)		(1,377)		(1,377)
Other comprehensive income (loss)	5			5	5			5
Stock-settled share-based compensation	38	38			38	38
Other					(71)				(71)
Balance at Mar. 31, 2022	3,624	8,953	(844)	(937)	3,593	355	1,600	(937)	2,575
Balance at Dec. 31, 2022	6,896	8,986	1,265	175	6,865	403	3,716	175	2,571
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(194)		(194)		(194)		(194)
Other comprehensive income (loss)	(14)			(14)	(14)			(14)
Stock-settled share-based compensation	11	11			11	11
Other					(32)				(32)
Balance at Mar. 31, 2023	$ 6,668	$ 8,926	$ 1,020	$ 161	$ 6,636	$ 414	$ 3,522	$ 161	$ 2,539