Business Combinations and Divestitures Other 2019 Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 2,832	$ 2,692	$ 2,741
Other Hospitality Acquisitions
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	20
Business Combination, Consideration Transferred, Liabilities Incurred	2
Goodwill	17
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 6
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	8 years