Revenue Recognition - Contract Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Contract liabilities
Contract liabilities	$ 204	$ 206
Deferred Revenue Related To Prepaid Stored Value Products [Member]
Contract liabilities
Contract liabilities	117	117
Deferred Revenue Related To Upfront Franchise Fees [Member]
Contract liabilities
Contract liabilities	39	38
Deferred Revenue Related To Customer Loyalty Programs [Member]
Contract liabilities
Contract liabilities	26	23
Deferred Revenue Related To Privilege Membership Programs [Member]
Contract liabilities
Contract liabilities	21	27
Others [Member]
Contract liabilities
Contract liabilities	$ 1	$ 1