Statements of Consolidated Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash Flows from Operating Activities:
Net cash provided by operating activities	$ 393	$ 124
Cash Flows from Investing Activities:
Capital expenditures and aircraft purchase deposits paid	(375)	(301)
Increase in short-term and other investments, net	(77)	(148)
Proceeds from sale of property and equipment	9	89
(Increase) decrease in restricted cash, net	12	(2)
Net cash used in investing activities	(431)	(362)
Cash Flows from Financing Activities:
Payments of long-term debt	(1,241)	(479)
Proceeds from issuance of long-term debt	109	86
Principal payments under capital leases	(29)	(23)
Other, net	(33)	14
Net cash used in financing activities	(1,194)	(402)
Net decrease in cash and cash equivalents during the period	(1,232)	(640)
Cash and cash equivalents at beginning of the period	4,770	6,246
Cash and cash equivalents at end of the period	3,538	5,606
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	146	136
Airport construction financing	5	16
United Airlines, Inc.
Cash Flows from Operating Activities:
Net cash provided by operating activities	389	124
Cash Flows from Investing Activities:
Capital expenditures and aircraft purchase deposits paid	(375)	(301)
Increase in short-term and other investments, net	(77)	(148)
Proceeds from sale of property and equipment	9	89
(Increase) decrease in restricted cash, net	12	(2)
Net cash used in investing activities	(431)	(362)
Cash Flows from Financing Activities:
Payments of long-term debt	(1,241)	(479)
Proceeds from issuance of long-term debt	109	86
Principal payments under capital leases	(29)	(23)
Other, net	(30)	14
Net cash used in financing activities	(1,191)	(402)
Net decrease in cash and cash equivalents during the period	(1,233)	(640)
Cash and cash equivalents at beginning of the period	4,765	6,240
Cash and cash equivalents at end of the period	3,532	5,600
Investing and Financing Activities Not Affecting Cash:
Property and equipment acquired through the issuance of debt	146	136
Airport construction financing	$ 5	$ 16