Components of Net Periodic Benefit Cost (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Benefits | United Continental Holdings Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25	$ 23	$ 50	$ 44
Interest cost	46	45	92	89
Expected return on plan assets	(35)	(35)	(70)	(69)
Amortization of unrecognized (gain) loss and prior service cost	6	(7)	11	(12)
Net periodic benefit costs	42	26	83	52
Pension Benefits | United Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	4	3
Interest cost	2	3	4	5
Expected return on plan assets	(3)	(3)	(6)	(5)
Amortization of unrecognized (gain) loss and prior service cost		(1)		(1)
Net periodic benefit costs	1	1	2	2
Pension Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	23	21	46	41
Interest cost	44	42	88	84
Expected return on plan assets	(32)	(32)	(64)	(64)
Amortization of unrecognized (gain) loss and prior service cost	6	(6)	11	(11)
Net periodic benefit costs	41	25	81	50
Other Postretirement Benefits | United Continental Holdings Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	13	12	26	24
Interest cost	32	32	63	63
Expected return on plan assets	(1)		(2)	(1)
Amortization of unrecognized (gain) loss and prior service cost	(1)	(1)	(2)	(1)
Net periodic benefit costs	43	43	85	85
Other Postretirement Benefits | United Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	8	18	17
Interest cost	28	28	55	56
Expected return on plan assets	(1)		(2)	(1)
Amortization of unrecognized (gain) loss and prior service cost	(1)		(2)
Net periodic benefit costs	35	36	69	72
Other Postretirement Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4	8	7
Interest cost	4	4	8	7
Amortization of unrecognized (gain) loss and prior service cost		(1)		(1)
Net periodic benefit costs	$ 8	$ 7	$ 16	$ 13