Schedule of Acquisition of Aircrafts and Related Spare Engines (Detail) (USD $) In Billions, unless otherwise specified	Jun. 30, 2012
United Continental Holdings Inc
Commitments and Contingencies Disclosure [Line Items]
Last six months of 2012	$ 1.2
2013	1.4
2014	1.3
2015	2.1
2016	2.8
After 2016	9.7
Total commitments	18.5
United Airlines Inc
Commitments and Contingencies Disclosure [Line Items]
Last six months of 2012	0.3
2013	0.4
2014	0.6
2015	0.8
2016	2.0
After 2016	7.2
Total commitments	11.3
Continental Airlines Inc
Commitments and Contingencies Disclosure [Line Items]
Last six months of 2012	0.9
2013	1.0
2014	0.7
2015	1.3
2016	0.8
After 2016	2.5
Total commitments	$ 7.2