Revenue Recognition - Contract Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Contract liabilities
Contract liabilities	$ 177	$ 168
Deferred Revenue Related To Prepaid Stored Value Products [Member]
Contract liabilities
Contract liabilities	90	86
Deferred Revenue Related To Upfront Franchise Fees [Member]
Contract liabilities
Contract liabilities	36	39
Deferred Revenue Related To Customer Loyalty Programs [Member]
Contract liabilities
Contract liabilities	27	24
Deferred Revenue Related To Privilege Membership Programs [Member]
Contract liabilities
Contract liabilities	22	16
Others [Member]
Contract liabilities
Contract liabilities	$ 2	$ 3