Statements of Consolidated Stockholder's Equity - USD ($) shares in Millions, $ in Millions	Total	United Airlines, Inc.	Common Stock	Additional Capital Invested	Additional Capital Invested United Airlines, Inc.	Treasury Stock	Accumulated Deficit	Accumulated Deficit United Airlines, Inc.	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) United Airlines, Inc.	Receivable from Related Parties, Net United Airlines, Inc.
Beginning Balance (in shares) at Dec. 31, 2013			362
Beginning Balance at Dec. 31, 2013	$ 2,984	$ 3,223	$ 4	$ 7,425	$ 7,590	$ (38)	$ (5,015)	$ (4,743)	$ 608	$ 608	$ (232)
Net income	1,132	1,114					1,132	1,114
Other comprehensive income (loss)	(1,687)	(1,687)							(1,687)	(1,687)
Convertible debt redemption (in shares)			17
Convertible debt redemption	260	156		260	156
Repurchase of convertible debt	(34)			(34)
Dividend and other capital distributions to UAL		(236)			(469)			1			232
Share-based compensation	10	10		10	10
Proceeds from exercise of stock options (in shares)			2
Proceeds from exercise of stock options	60			60
UAL contribution related to stock plans		60			60
Repurchases of common stock	(320)					(320)
Repurchases of common stock (in shares)			(6)
Other	(9)	(5)				(9)					(5)
Ending Balance (in shares) at Dec. 31, 2014			375
Ending Balance at Dec. 31, 2014	2,396	2,635	$ 4	7,721	7,347	(367)	(3,883)	(3,628)	(1,079)	(1,079)	(5)
Net income	7,340	7,301					7,340	7,301
Other comprehensive income (loss)	248	248							248	248
Convertible debt redemption (in shares)			11
Convertible debt redemption	202			202
Dividend and other capital distributions to UAL		(1,232)			(1,232)
Share-based compensation	7	7		7	7
Proceeds from exercise of stock options	16			16
UAL contribution related to stock plans		16			16
Repurchases of common stock	(1,232)					(1,232)
Repurchases of common stock (in shares)			(21)
Other	(11)	(12)				(11)					(12)
Ending Balance (in shares) at Dec. 31, 2015			365
Ending Balance at Dec. 31, 2015	8,966	8,963	$ 4	7,946	6,138	(1,610)	3,457	3,673	(831)	(831)	(17)
Net income	2,263	2,264					2,263	2,264
Other comprehensive income (loss)	2	2							2	2
Dividend and other capital distributions to UAL		(2,603)			(2,603)
Share-based compensation	32	32		32	32
Proceeds from exercise of stock options	6			6
UAL contribution related to stock plans		6			6
Repurchases of common stock	$ (2,607)					(2,607)
Repurchases of common stock (in shares)	(50)		(50)
Treasury stock retired			$ (1)	(1,415)		3,709	(2,293)
Other	$ (3)	(58)				(3)					(58)
Ending Balance (in shares) at Dec. 31, 2016			315
Ending Balance at Dec. 31, 2016	$ 8,659	$ 8,606	$ 3	$ 6,569	$ 3,573	$ (511)	$ 3,427	$ 5,937	$ (829)	$ (829)	$ (75)