Segment Information (Summary of Net Revenues and Adjusted EBITDA by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net Revenues	$ 258	$ 533	$ 667	$ 1,001
Adjusted EBITDA	63	159	170	270
Reportable Segments
Segment Reporting Information [Line Items]
Net Revenues	258	532	667	998
Adjusted EBITDA	79	178	204	306
Reportable Segments | Hotel Franchising
Segment Reporting Information [Line Items]
Net Revenues	182	331	425	600
Adjusted EBITDA	83	162	191	275
Reportable Segments | Hotel Management
Segment Reporting Information [Line Items]
Net Revenues	76	201	242	398
Adjusted EBITDA	(4)	16	13	31
Corporate and Other
Segment Reporting Information [Line Items]
Net Revenues	0	1	0	3
Adjusted EBITDA	$ (16)	$ (19)	$ (34)	$ (36)