SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Effect of Adoption of ASU 2014-09 on Balance Sheets (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and equivalents		$ 316	$ 383
Accounts and notes receivable, net	[1]	2,133	1,973
Prepaid expenses and other	[1]	249	235
Assets held for sale		8	149
Assets, current, total		2,706	2,740
Property and equipment, net		1,956	1,793
Intangible assets		8,380	8,544
Goodwill		9,039	9,207
Goodwill and intangible assets, net, total		17,419	17,751
Equity method investments	[1]	732	734
Notes receivable, net		125	142
Deferred tax assets		171	93
Other noncurrent assets	[1]	587	593
Total assets		23,696	23,846
Current liabilities
Current portion of long-term debt		833	398
Accounts payable	[1]	767	783
Accrued payroll and benefits		1,345	1,214
Accrued expenses and other	[1]	963	1,291
Liabilities, current, total		6,437	5,807
Long-term debt		8,514	7,840
Deferred tax liabilities	[1]	485	605
Other noncurrent liabilities	[1]	2,372	2,610
Shareholders’ equity
Class A Common Stock		5	5
Additional paid-in-capital		5,814	5,770
Retained earnings		8,982	7,242
Treasury stock, at cost		(12,185)	(9,418)
Accumulated other comprehensive loss		(391)	(17)
Shareholder's equity (deficit)		2,225	3,582
Liabilities and deficit, total		23,696	23,846
Brands
Current assets
Intangible assets		5,790	5,922
Contract acquisition costs and other
Current assets
Intangible assets	[1]	2,590	2,622
Guest loyalty program
Current liabilities
Liability for guest loyalty program		2,529	2,121
Contract with customer		2,932	2,819
Deferred revenue
Current liabilities
Contract with customer		$ 731	583
As Previously Reported
Current assets
Cash and equivalents			383
Accounts and notes receivable, net			1,999
Prepaid expenses and other			216
Assets held for sale			149
Assets, current, total			2,747
Property and equipment, net			1,793
Goodwill			9,207
Goodwill and intangible assets, net, total			18,013
Equity method investments			735
Notes receivable, net			142
Deferred tax assets			93
Other noncurrent assets			426
Total assets			23,949
Current liabilities
Current portion of long-term debt			398
Accounts payable			783
Accrued payroll and benefits			1,214
Accrued expenses and other			1,541
Liabilities, current, total			6,000
Long-term debt			7,840
Deferred tax liabilities			604
Other noncurrent liabilities			2,753
Shareholders’ equity
Class A Common Stock			5
Additional paid-in-capital			5,770
Retained earnings			7,391
Treasury stock, at cost			(9,418)
Accumulated other comprehensive loss			(17)
Shareholder's equity (deficit)			3,731
Liabilities and deficit, total			23,949
As Previously Reported | Brands
Current assets
Intangible assets			5,922
As Previously Reported | Contract acquisition costs and other
Current assets
Intangible assets			2,884
As Previously Reported | Guest loyalty program
Current liabilities
Liability for guest loyalty program			2,064
Contract with customer			2,876
As Previously Reported | Deferred revenue
Current liabilities
Contract with customer			145
Accounting Standards Update 2014-09 | Adoption of ASU
Current assets
Cash and equivalents			0
Accounts and notes receivable, net			(26)
Prepaid expenses and other			19
Assets held for sale			0
Assets, current, total			(7)
Property and equipment, net			0
Goodwill			0
Goodwill and intangible assets, net, total			(262)
Equity method investments			(1)
Notes receivable, net			0
Deferred tax assets			0
Other noncurrent assets			167
Total assets			(103)
Current liabilities
Current portion of long-term debt			0
Accounts payable			0
Accrued payroll and benefits			0
Accrued expenses and other			(250)
Liabilities, current, total			(193)
Long-term debt			0
Deferred tax liabilities			1
Other noncurrent liabilities			(143)
Shareholders’ equity
Class A Common Stock			0
Additional paid-in-capital			0
Retained earnings			(149)
Treasury stock, at cost			0
Accumulated other comprehensive loss			0
Shareholder's equity (deficit)			(149)
Liabilities and deficit, total			(103)
Accounting Standards Update 2014-09 | Adoption of ASU | Brands
Current assets
Intangible assets			0
Accounting Standards Update 2014-09 | Adoption of ASU | Contract acquisition costs and other
Current assets
Intangible assets			(262)
Accounting Standards Update 2014-09 | Adoption of ASU | Guest loyalty program
Current liabilities
Liability for guest loyalty program			57
Contract with customer			(57)
Accounting Standards Update 2014-09 | Adoption of ASU | Deferred revenue
Current liabilities
Contract with customer			$ 438

[1] See Footnote 18. Related Party Transactions for disclosure of related party amounts.