Pension And Other Postretirement Plans (Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Pension Benefits [Member]	Dec. 31, 2010 Pension Benefits [Member]	Dec. 31, 2011 Other Postretirement Benefits [Member]	Dec. 31, 2010 Other Postretirement Benefits [Member]	Dec. 31, 2009 UAL And United [Member] Pension Benefits [Member]	Dec. 31, 2009 UAL And United [Member] Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 88	$ 27	$ 47	$ 33	$ 6	$ 28
Interest cost	178	51	127	120	8	114
Expected return on plan assets	(140)	(39)	(2)	(2)	(7)	(4)
Curtailment gain		(7)			(1)	(9)
Amortization of prior service cost (credit)	(2)	(2)
Special termination benefits		4
Amortization of unrecognized actuarial (gain) loss	(20)	1	(2)	(12)	2	(20)
Net periodic benefit cost	105	35	170	139	8	109
Settlement (gain) loss	1
Net benefit expense					$ 8	$ 109