Hedging Activities (Derivatives Not Designated As Cash Flow Hedges) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments, Gain (Loss) [Line Items]
Nonoperating Income (Expense)	$ (977)	$ (723)	$ (507)
United Airlines Inc [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Nonoperating Income (Expense)	(603)	(631)	(507)
UAL And United [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Aircraft Fuel Gain (Loss)		(35)	104
Nonoperating Income (Expense)			31
Total Gain (Loss)		$ (35)	$ 135

The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_NonoperatingIncomeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration