Pension And Other Postretirement Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Pension And Other Postretirement Plans [Abstract]
Percentage of pre-tax earnings	15.00%
Minimum pre-tax profit before employee participation in profit sharing	$ 10
Present value of liability	$ 525

Minimum pre-tax profit before employee participation in profit sharing.

No definition available.

Name:	ual_MinimumPreTaxProfitBeforeEmployeeParticipationInProfitSharing
Namespace Prefix:	ual_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration