Leases - Schedule of Operating and Finance Lease Assets and Liabilities are Included on Consolidated Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Noncurrent Lease Assets:
Finance lease		$ 95	$ 105
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		trip:PropertyAndEquipmentNetMember	trip:PropertyAndEquipmentNetMember
Operating lease right-of-use assets (Note 7)		$ 54	$ 74
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		trip:OperatingLeaseRightOfUseAssetsMember	trip:OperatingLeaseRightOfUseAssetsMember
Total noncurrent lease assets		$ 149	$ 179
Current Lease Liabilities:
Finance lease	[1]	$ 5	$ 5
Finance Lease Liability Current Statement Of Financial Position Extensible List		trip:AccruedExpensesAndOtherCurrentLiabilitiesMember	trip:AccruedExpensesAndOtherCurrentLiabilitiesMember
Operating lease	[1]	$ 21	$ 20
Operating Lease Liability Current Statement Of Financial Position Extensible List		trip:AccruedExpensesAndOtherCurrentLiabilitiesMember	trip:AccruedExpensesAndOtherCurrentLiabilitiesMember
Current Lease Liabilities		$ 26	$ 25
Noncurrent Lease Liabilities:
Finance lease obligation, net of current portion (Note 7)		$ 71	$ 78
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		trip:FinanceLeaseObligationNetOfCurrentPortionMember	trip:FinanceLeaseObligationNetOfCurrentPortionMember
Operating lease liabilities, net of current portion (Note 7)		$ 46	$ 64
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		trip:OperatingLeaseLiabilitiesNetOfCurrentPortionMember	trip:OperatingLeaseLiabilitiesNetOfCurrentPortionMember
Lease Liabilities Noncurrent		$ 117	$ 142
Finance Lease Liability		$ 143	$ 167

[1] Refer to “Note 7: Leases” for further information regarding our lease obligations.