Revenue Recognition (Contract Liabilities) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 436	$ 448	$ 558	$ 539
Contract with Customer, Liability, Revenue Recognition Term		1 year
Deferred subscription revenue
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 181	176
Deferred VOI trial package revenue
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 109	115
Deferred VOI trial package revenue | Vacation Ownership
Disaggregation of Revenue [Line Items]
Contract with Customer, Liability, Revenue Recognition Term		1 year
Deferred VOI incentive revenue
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 66	74
Deferred exchange-related revenue
Disaggregation of Revenue [Line Items]
Contract liabilities	[1]	$ 63	59
Deferred exchange-related revenue | Travel and Membership
Disaggregation of Revenue [Line Items]
Contract with Customer, Liability, Revenue Recognition Term		1 year
Deferred co-branded credit card programs revenue
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 14	16
Deferred other revenue
Disaggregation of Revenue [Line Items]
Contract liabilities		$ 3	$ 8

[1] Includes contractual liabilities to accommodate members for cancellations initiated by the Company due to unexpected events. These amounts are included within Accrued expenses and other liabilities on the Condensed Consolidated Balance Sheets.