Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Contract and Contract Related Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding Chip Liability [Member]
Contract and Contract Related Liabilities [Line Items]
Contract and contract related, liability		$ 211	$ 540	$ 551
Change in contract and contract related liabilities		(329)	(11)
Loyalty Program Liability [Member]
Contract and Contract Related Liabilities [Line Items]
Contract and contract related, liability		68	68	66
Change in contract and contract related liabilities		0	2
Customer Deposits and Other Deferred Revenue [Member]
Contract and Contract Related Liabilities [Line Items]
Contract and contract related, liability	[1]	751	724	827
Change in contract and contract related liabilities		27	(103)
Mall [Member] | Customer Deposits and Other Deferred Revenue [Member]
Contract and Contract Related Liabilities [Line Items]
Contract and contract related, liability	[1]	$ 152	$ 154	$ 152

[1] Of this amount, $152 million, $154 million and $152 million as of December 31, 2020 and 2019 and January 1, 2019, respectively, relates to mall deposits that are accounted for based on lease terms usually greater than one year.