Condensed Statements of Consolidated Cash Flows (Unaudited) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Cash Flows from Operating Activities:
Net cash provided (used) by operating activities		$ 63	$ 1,915
Cash Flows from Investing Activities:
Capital expenditures		(1,959)	(1,609)
Purchases of short-term and other investments		(541)	(724)
Proceeds from sale of short-term and other investments		927	768
Other, net		1	(15)
Net cash used in investing activities		(1,572)	(1,580)
Cash Flows from Financing Activities:
Proceeds from issuance of short-term debt		2,500	0
Proceeds from issuance of long-term debt		348	646
Payments of long-term debt		(235)	(250)
Repurchases of common stock		(353)	(513)
Principal payments under finance leases		(18)	(20)
Capitalized financing costs		(35)	(17)
Other, net		(18)	(29)
Net cash provided (used) in financing activities		2,189	(183)
Net increase in cash, cash equivalents and restricted cash		680	152
Cash, cash equivalents and restricted cash at beginning of the period		2,868	1,799
Cash, cash equivalents and restricted cash at end of the period	[1]	3,548	1,951
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt		109	92
Lease modifications and lease conversions		439	36
Right-of-use assets acquired through operating leases		30	51
Property and equipment acquired through finance leases		19	8
United Airlines, Inc.
Cash Flows from Operating Activities:
Net cash provided (used) by operating activities		45	1,886
Cash Flows from Investing Activities:
Capital expenditures		(1,959)	(1,609)
Purchases of short-term and other investments		(541)	(724)
Proceeds from sale of short-term and other investments		927	768
Other, net		1	(15)
Net cash used in investing activities		(1,572)	(1,580)
Cash Flows from Financing Activities:
Proceeds from issuance of short-term debt		2,500	0
Proceeds from issuance of long-term debt		348	646
Payments of long-term debt		(235)	(250)
Dividend to UAL		(353)	(513)
Principal payments under finance leases		(18)	(20)
Capitalized financing costs		(35)	(17)
Net cash provided (used) in financing activities		2,207	(154)
Net increase in cash, cash equivalents and restricted cash		680	152
Cash, cash equivalents and restricted cash at beginning of the period		2,862	1,793
Cash, cash equivalents and restricted cash at end of the period	[2]	3,542	1,945
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt		109	92
Lease modifications and lease conversions		439	36
Right-of-use assets acquired through operating leases		30	51
Property and equipment acquired through finance leases		$ 19	$ 8

[1] The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts reported within the consolidated balance sheet: Cash and cash equivalents $ 3,442
  $ 1,848
Restricted cash 106
  103
Total cash, cash equivalents and restricted cash $ 3,548
  $ 1,951

[2] The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts reported within the consolidated balance sheet: Cash and cash equivalents $ 3,436
  $ 1,842
Restricted cash 106
  103
Total cash, cash equivalents and restricted cash $ 3,542
  $ 1,945