Statements of Consolidated Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Operating revenue:
Revenue	$ 43,259	$ 41,303	[1]	$ 37,784	[1]
Operating expense:
Salaries and related costs	12,071	11,458	[1]	10,941	[1]
Aircraft fuel	8,953	9,307	[1]	6,913	[1]
Regional capacity purchase	2,849	2,649	[1]	2,268	[1]
Landing fees and other rent	2,543	2,449	[1]	2,310	[1]
Depreciation and amortization	2,288	2,165	[1],[2]	2,096	[1],[2]
Aircraft maintenance materials and outside repairs	1,794	1,767	[1]	1,856	[1]
Distribution expenses	1,651	1,558	[1]	1,435	[1]
Aircraft rent	288	433	[1]	621	[1]
Special charges	246	487	[1]	176	[1]
Other operating expenses	6,275	5,801	[1]	5,550	[1]
Total operating expense	38,958	38,074	[1]	34,166	[1]
Operating income	4,301	3,229	[1]	3,618	[1]
Nonoperating income (expense):
Interest expense	(731)	(670)	[1]	(626)	[1]
Interest capitalized	85	65	[1]	74	[1]
Interest income	133	101	[1]	57	[1]
Unrealized gains (losses) on investments, net	153	(5)	[1],[2]	0	[1],[2]
Miscellaneous, net	(27)	(72)	[1]	(100)	[1]
Total nonoperating expense, net	(387)	(581)	[1]	(595)	[1]
Income before income taxes	3,914	2,648	[1]	3,023	[1]
Income tax expense	905	526	[1]	880	[1]
Net income	$ 3,009	$ 2,122	[1],[2],[3],[4]	$ 2,143	[1],[2],[3],[4]
Earnings per share, basic (in dollars per share)	$ 11.63	$ 7.70	[1]	$ 7.08	[1]
Earnings per share, diluted (in dollars per share)	$ 11.58	$ 7.67	[1]	$ 7.06	[1]
United Airlines, Inc.
Operating revenue:
Revenue	$ 43,259	$ 41,303	[5]	$ 37,784	[5]
Operating expense:
Salaries and related costs	12,071	11,458	[5]	10,941	[5]
Aircraft fuel	8,953	9,307	[5]	6,913	[5]
Regional capacity purchase	2,849	2,649	[5]	2,268	[5]
Landing fees and other rent	2,543	2,449	[5]	2,310	[5]
Depreciation and amortization	2,288	2,165	[5],[6]	2,096	[5],[6]
Aircraft maintenance materials and outside repairs	1,794	1,767	[5]	1,856	[5]
Distribution expenses	1,651	1,558	[5]	1,435	[5]
Aircraft rent	288	433	[5]	621	[5]
Special charges	246	487	[5]	176	[5]
Other operating expenses	6,273	5,799	[5]	5,548	[5]
Total operating expense	38,956	38,072	[5]	34,164	[5]
Operating income	4,303	3,231	[5]	3,620	[5]
Nonoperating income (expense):
Interest expense	(731)	(670)	[5]	(626)	[5]
Interest capitalized	85	65	[5]	74	[5]
Interest income	133	101	[5]	57	[5]
Unrealized gains (losses) on investments, net	153	(5)	[5],[6]	0	[5],[6]
Miscellaneous, net	(27)	(72)	[5]	(100)	[5]
Total nonoperating expense, net	(387)	(581)	[5]	(595)	[5]
Income before income taxes	3,916	2,650	[5]	3,025	[5]
Income tax expense	905	527	[5]	864	[5]
Net income	3,011	2,123	[5],[6],[7],[8]	2,161	[5],[6],[7],[8]
Passenger revenue
Operating revenue:
Revenue	39,625	37,706	[1]	34,460	[1]
Passenger revenue | United Airlines, Inc.
Operating revenue:
Revenue	39,625	37,706	[5]	34,460	[5]
Cargo
Operating revenue:
Revenue	1,179	1,237	[1]	1,114	[1]
Cargo | United Airlines, Inc.
Operating revenue:
Revenue	1,179	1,237	[5]	1,114	[5]
Other operating revenue
Operating revenue:
Revenue	2,455	2,360	[1]	2,210	[1]
Other operating revenue | United Airlines, Inc.
Operating revenue:
Revenue	$ 2,455	$ 2,360	[5]	$ 2,210	[5]

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[2] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[3] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8

[4] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[5] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[6] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[7] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.

[8] Amounts adjusted due to the adoption of Accounting Standards Update No. 2016-02, Leases (Topic 842). See Note 1 to the financial statements contained in Part II, Item 8 of this report for additional information.