XML 52 R37.htm IDEA: XBRL DOCUMENT
v3.22.1

Revenue - Roll Forward of Frequent Flyer Deferred Revenue (Details) - Frequent Flyer - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2022 | Mar. 31, 2021
Frequent Flyer Deferred Revenue [Roll Forward] |  |
Total Frequent flyer deferred revenue - beginning balance | $ 6,282 | $ 5,975
Total miles awarded | 477 | 272
Travel miles redeemed | (322) | (123)
Non-travel miles redeemed | (20) | (15)
Total Frequent flyer deferred revenue - ending balance | $ 6,417 | $ 6,109

X
- Definition Frequent flyer mileage miles awarded in period. + References No definition available. + Details
Name: | ual_FrequentFlyerMileageMilesAwardedInPeriod
Namespace Prefix: | ual_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Movement In Contract With Customer Liability [Roll Forward] + References No definition available. + Details
Name: | ual_MovementInContractWithCustomerLiabilityRollForward
Namespace Prefix: | ual_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Non-travel miles redemption, frequent flyer deferred revenue. + References No definition available. + Details
Name: | ual_NonTravelMilesRedemptionFrequentFlyerDeferredRevenue
Namespace Prefix: | ual_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Travel miles redemption, frequent flyer deferred revenue. + References No definition available. + Details
Name: | ual_TravelMilesRedemptionFrequentFlyerDeferredRevenue
Namespace Prefix: | ual_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130531-203044 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130532-203044 + Details
Name: | us-gaap_ContractWithCustomerLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | srt_ProductOrServiceAxis=ual_FrequentFlyerProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |