Merger-Related Costs and Charges Merger-Related Costs and Charges- Types of Merger-related Costs and Charges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Merger-related costs and charges
Transaction, employee termination and integration costs	$ 28	$ 228	$ 100	$ 250
Interest expense	73	55	216	159
Starwood Hotels & Resorts Worldwide, Inc.
Merger-related costs and charges
Transaction costs	4	18	14	31
Employee termination costs	(3)	186	9	186
Integration costs	27	24	77	33
Transaction, employee termination and integration costs	28	228	100	250
Interest expense	0	9	0	22
Transaction, employee termination, integration, and interest costs	$ 28	$ 237	$ 100	$ 272