Revenue Recognition Revenue Recognition - Retail Value of Complimentaries (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Promotional Allowances	$ 272	$ 280
Food and Beverage [Member]
Promotional Allowances	149	151
Rooms [Member]
Promotional Allowances	108	115
Other [Member]
Promotional Allowances	$ 15	$ 14

This element represents the estimated retail value of accommodations, food and beverage, and other services furnished to guests without charge.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 605
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=68080496&loc=d3e51325-107943

Name:	us-gaap_PromotionalAllowances
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration