Pension and Other Postretirement Plan Assets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	$ 2,157	$ 1,868	$ 1,871
Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,034	872
Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	611	530
Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	394	344
Pension Benefits | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	36	42
Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	82	80
Pension Benefits | United Air Lines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	221	195	183
Pension Benefits | United Air Lines Inc | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	125	102
Pension Benefits | United Air Lines Inc | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	56	47
Pension Benefits | United Air Lines Inc | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	36	42
Pension Benefits | United Air Lines Inc | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	4	4
Pension Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,936	1,673	1,688
Pension Benefits | Continental Airlines Inc | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	909	770
Pension Benefits | Continental Airlines Inc | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	555	483
Pension Benefits | Continental Airlines Inc | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	394	344
Pension Benefits | Continental Airlines Inc | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	78	76
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	58	58	58
Other Postretirement Benefits | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	58	58
Other Postretirement Benefits | United Air Lines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	58	58	58
Other Postretirement Benefits | United Air Lines Inc | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	58	58
Level 1 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	383	355
Level 1 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	383	355
Level 1 | Pension Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	383	355
Level 1 | Pension Benefits | Continental Airlines Inc | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	383	355
Level 2 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,576	1,322
Level 2 | Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	651	517
Level 2 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	609	530
Level 2 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	234	195
Level 2 | Pension Benefits | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	82	80
Level 2 | Pension Benefits | United Air Lines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	185	153
Level 2 | Pension Benefits | United Air Lines Inc | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	125	102
Level 2 | Pension Benefits | United Air Lines Inc | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	56	47
Level 2 | Pension Benefits | United Air Lines Inc | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	4	4
Level 2 | Pension Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	1,391	1,169
Level 2 | Pension Benefits | Continental Airlines Inc | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	526	415
Level 2 | Pension Benefits | Continental Airlines Inc | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	553	483
Level 2 | Pension Benefits | Continental Airlines Inc | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	234	195
Level 2 | Pension Benefits | Continental Airlines Inc | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	78	76
Level 3
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	256	249	250
Level 3 | United Air Lines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	94	100	100
Level 3 | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	162	149	150
Level 3 | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	198	191
Level 3 | Pension Benefits | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	2
Level 3 | Pension Benefits | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	160	149
Level 3 | Pension Benefits | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	36	42
Level 3 | Pension Benefits | United Air Lines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	36	42
Level 3 | Pension Benefits | United Air Lines Inc | Insurance Contract
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	36	42
Level 3 | Pension Benefits | Continental Airlines Inc
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	162	149
Level 3 | Pension Benefits | Continental Airlines Inc | Fixed-Income Securities
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	2
Level 3 | Pension Benefits | Continental Airlines Inc | Alternatives
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	160	149
Level 3 | Other Postretirement Benefits | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	58	58
Level 3 | Other Postretirement Benefits | United Air Lines Inc | Deposit Administration Fund
Defined Benefit Plan Disclosure [Line Items]
Pension and other postretirement plan assets	$ 58	$ 58