Marriott International (MAR) 10-K 18 Feb 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 10, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-13881
Entity Registrant Name	MARRIOTT INTERNATIONAL INC /MD/
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	52-2055918
Entity Address, Address Line One	10400 Fernwood Road
Entity Address, City or Town	Bethesda
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20817
City Area Code	301
Local Phone Number	380-3000
Title of 12(b) Security	Class A Common Stock, $0.01 par value
Trading Symbol	MAR
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 23,156,431,539
Entity Common Stock, Shares Outstanding		324,414,150
Documents Incorporated by Reference	Portions of the Proxy Statement prepared for the 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this report.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001048286
Current Fiscal Year End Date	--12-31

CONSOLIDATED STATEMENTS OF (LOS

CONSOLIDATED STATEMENTS OF (LOSS) INCOME - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUES
Total revenue		$ 10,571	$ 20,972	$ 20,758
OPERATING COSTS AND EXPENSES
Depreciation, amortization, and other		346	341	226
General, administrative, and other		762	938	927
Restructuring and merger-related charges		267	138	155
Costs and Expenses, Total		10,487	19,172	18,392
OPERATING INCOME		84	1,800	2,366
Gains and other income, net	[1]	9	154	194
Interest expense	[1]	(445)	(394)	(340)
Interest income	[1]	27	26	22
Equity in (losses) earnings	[1]	(141)	13	103
(LOSS) INCOME BEFORE INCOME TAXES		(466)	1,599	2,345
Benefit (provision) for income taxes		199	(326)	(438)
NET (LOSS) INCOME		$ (267)	$ 1,273	$ 1,907
(LOSS) EARNINGS PER SHARE
(Loss) earnings per share - basic (in USD per share)		$ (0.82)	$ 3.83	$ 5.45
(Loss) earnings per share - diluted (in USD per share)		$ (0.82)	$ 3.80	$ 5.38
Base management fees
REVENUES
Gross fee revenues		$ 443	$ 1,180	$ 1,140
Franchise fees
REVENUES
Gross fee revenues		1,153	2,006	1,849
Incentive management fees
REVENUES
Gross fee revenues		87	637	649
Net fee revenues
REVENUES
Gross fee revenues		1,683	3,823	3,638
Contract investment amortization		(132)	(62)	(58)
Total revenue		1,551	3,761	3,580
Owned, leased, and other
REVENUES
Total revenue		568	1,612	1,635
OPERATING COSTS AND EXPENSES
Cost of revenues		677	1,316	1,306
Reimbursements
REVENUES
Total revenue	[1]	8,452	15,599	15,543
OPERATING COSTS AND EXPENSES
Cost of revenues	[1]	$ 8,435	$ 16,439	$ 15,778
[1]	See Note 16 for disclosure of related party amounts.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ (267)	$ 1,273	$ 1,907
Other comprehensive (loss) income:
Foreign currency translation adjustments	229	35	(391)
Derivative instrument adjustments and other, net of tax	(3)	(5)	21
Total other comprehensive income (loss), net of tax	226	30	(370)
Comprehensive (loss) income	$ (41)	$ 1,303	$ 1,537

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and equivalents	$ 877	$ 225
Accounts and notes receivable, net	1,768	2,395
Prepaid expenses and other	172	252
Assets held for sale	8	255
Assets, current, total	2,825	3,127
Property and equipment, net	1,514	1,904
Intangible assets
Intangible assets	8,989	8,641
Goodwill	9,175	9,048
Goodwill and intangible assets, net, total	18,164	17,689
Equity method investments	422	577
Notes receivable, net	159	117
Deferred tax assets	249	154
Operating lease assets	752	888
Other noncurrent assets	616	595
Total assets	24,701	25,051
Current liabilities
Current portion of long-term debt	1,173	977
Accounts payable	527	720
Accrued payroll and benefits	831	1,339
Accrued expenses and other	1,452	1,383
Liabilities, current, total	5,752	6,677
Long-term debt	9,203	9,963
Deferred tax liabilities	83	290
Operating lease liabilities	823	882
Other noncurrent liabilities	2,366	2,236
Stockholders’ equity
Class A Common Stock	5	5
Additional paid-in-capital	5,851	5,800
Retained earnings	9,206	9,644
Treasury stock, at cost	(14,497)	(14,385)
Accumulated other comprehensive loss	(135)	(361)
Shareholder's equity (deficit)	430	703
Liabilities and deficit, total	24,701	25,051
Brands
Intangible assets
Intangible assets	6,059	5,954
Contract acquisition costs and other
Intangible assets
Intangible assets	2,930	2,687
Guest loyalty program
Current liabilities
Liability for guest loyalty program	1,769	2,258
Contract with customer	4,502	3,460
Deferred revenue
Current liabilities
Contract with customer	$ 1,542	$ 840

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)		Dec. 31, 2019USD ($)		Dec. 31, 2018USD ($)
OPERATING ACTIVITIES
Net (loss) income	$ (267)		$ 1,273		$ 1,907
Adjustments to reconcile to cash provided by operating activities:
Depreciation, amortization, and other	478		403		284
Stock-based compensation	201		187		184
Income taxes	(478)		(200)		(239)
Contract acquisition costs	(142)		(195)		(152)
Restructuring and merger-related charges	200		86		16
Working capital changes	(28)		(273)		(76)
Loss (gain) on asset dispositions	3		(147)		(194)
Deferred revenue changes and other	1,137		294		107
Net cash provided by operating activities	1,639		1,685		2,357
INVESTING ACTIVITIES
Capital and technology expenditures	(135)		(653)		(556)
Dispositions	260		395		479
Loan advances	(41)		(30)		(13)
Loan collections	8		51		48
Other	(57)		(47)		(10)
Net cash provided by (used in) investing activities	35		(284)		(52)
FINANCING ACTIVITIES
Commercial paper/Credit Facility, net	(2,290)		951		(129)
Issuance of long-term debt	3,561		1,397		1,646
Repayment of long-term debt	(1,887)		(835)		(397)
Issuance of Class A Common Stock	0		7		4
Dividends paid	(156)		(612)		(543)
Purchase of treasury stock	(150)		(2,260)		(2,850)
Stock-based compensation withholding taxes	(103)		(148)		(105)
Other	(8)		(8)		0
Net cash used in financing activities	(1,033)		(1,508)		(2,374)
INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	641		(107)		(69)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, beginning of period	253	[1]	360		429
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, end of period	894	[1]	253	[1]	360
Restricted cash	17		28
Guest loyalty program
Adjustments to reconcile to cash provided by operating activities:
Liability for guest loyalty program	$ 535		$ 257		$ 520
[1]	The 2020 amounts include beginning restricted cash of $28 million at December 31, 2019, and ending restricted cash of $17 million at December 31, 2020, which we present in the “Prepaid expenses and other” and “Other noncurrent assets” captions of our Balance Sheets.

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Class A Common StockClass A Common Stock		Additional Paid-in- Capital	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive LossCumulative Effect, Period of Adoption, Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)			359,100,000
Beginning balance at Dec. 31, 2017	$ 3,582		$ 5		$ 5,770	$ 7,242		$ (9,418)	$ (17)
Beginning balance (Accounting Standards Update 2016-01) at Dec. 31, 2017		$ 0					$ 4			$ (4)
Beginning balance (Accounting Standards Update 2016-16) at Dec. 31, 2017		372					372
Beginning balance (in shares) at Dec. 31, 2017			359,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,907					1,907
Other comprehensive income (loss)	(370)								(370)
Dividends	(543)					(543)
Stock-based compensation plans (in shares)			1,500,000
Stock-based compensation plans	86				44			42
Purchase of treasury stock	(2,809)							(2,809)
Purchase of treasury stock (in shares)			(21,500,000)
Ending balance at Dec. 31, 2018	2,225		$ 5		5,814	8,982		(12,185)	(391)
Ending balance (Accounting Standards Update 2016-02) at Dec. 31, 2018		1					1
Ending balance (in shares) at Dec. 31, 2018			339,100,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)			339,100,000
Common stock, outstanding (in shares)			339,100,000
Net income	1,273					1,273
Other comprehensive income (loss)	30								30
Dividends	(612)					(612)
Stock-based compensation plans (in shares)			2,200,000
Stock-based compensation plans	46				(14)			60
Purchase of treasury stock	(2,260)							(2,260)
Purchase of treasury stock (in shares)			(17,300,000)
Ending balance at Dec. 31, 2019	703		$ 5		5,800	9,644		(14,385)	(361)
Ending balance (Accounting Standards Update 2016-13) at Dec. 31, 2019		$ (15)					$ (15)
Ending balance (in shares) at Dec. 31, 2019			324,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)			324,000,000
Common stock, outstanding (in shares)			324,000,000
Net income	(267)
Other comprehensive income (loss)	226								226
Dividends	(156)					(156)
Stock-based compensation plans (in shares)			1,400,000
Stock-based compensation plans	89				51			38
Purchase of treasury stock	(150)							(150)
Purchase of treasury stock (in shares)			(1,000,000)
Ending balance at Dec. 31, 2020	$ 430		$ 5		$ 5,851	$ 9,206		$ (14,497)	$ (135)
Ending balance (in shares) at Dec. 31, 2020	324,400,000		324,400,000	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, outstanding (in shares)	324,400,000		324,400,000	[1]
Common stock, authorized (in shares)	800,000,000
Common stock, par value (in USD per share)	$ 0.01
Common stock, outstanding (in shares)	324,400,000		324,400,000	[1]
Preferred stock, authorized (in shares)	10,000,000
Preferred stock, outstanding (in shares)	0
[1]	Our restated certificate of incorporation authorizes 800 million shares of our common stock, with a par value of $0.01 per share and 10 million shares of preferred stock, without par value. At year-end 2020, we had 324.4 million of these authorized shares of our common stock and no preferred stock outstanding.

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared (in USD per share)	$ 0.48	$ 1.85	$ 1.56

BASIS OF PRESENTATION

BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The consolidated financial statements present the results of operations, financial position, and cash flows of Marriott International, Inc. and subsidiaries (referred to in this report as “we,” “us,” “Marriott,” or the “Company”). In order to make this report easier to read, we also refer throughout to (1) our Consolidated Financial Statements as our “Financial Statements,” (2) our Consolidated Statements of (Loss) Income as our “Income Statements,” (3) our Consolidated Balance Sheets as our “Balance Sheets,” (4) our Consolidated Statements of Cash Flows as our “Statements of Cash Flows,” (5) our properties, brands, or markets in the United States and Canada as “U.S. & Canada,” and (6) our properties, brands, or markets in our Caribbean and Latin America region, Europe, Middle East and Africa segment, and Asia Pacific segment as “International.” In addition, references throughout to numbered “Notes” refer to these Notes to Consolidated Financial Statements, unless otherwise stated. Preparation of financial statements that conform with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, the reported amounts of revenues and expenses during the reporting periods, and the disclosures of contingent liabilities. The uncertainty created by the coronavirus and efforts to contain it (“COVID-19”) has made such estimates more difficult and subjective. Accordingly, ultimate results could differ from those estimates. The accompanying Financial Statements reflect all normal and recurring adjustments necessary to present fairly our financial position at fiscal year-end 2020 and fiscal year-end 2019 and the results of our operations and cash flows for fiscal years 2020, 2019, and 2018. We have eliminated all material intercompany transactions and balances between entities consolidated in these Financial Statements. The accompanying Financial Statements also reflect our adoption of Accounting Standards Update (“ASU”) 2016-13. See the “New Accounting Standards Adopted” caption in Note 2 for additional information.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Revenue Recognition Base Management and Incentive Management Fees : For our managed hotels, we have performance obligations to provide hotel management services and a license to our intellectual property for the use of our brand names. As compensation for such services, we are generally entitled to receive base fees, which are a percentage of the revenues of hotels, and incentives fees, which are generally based on a measure of hotel profitability. Both the base and incentive management fees are variable consideration, as the transaction price is based on a percentage of revenue or profit, as defined in each contract. We recognize base management fees on a monthly basis over the term of the agreement as those amounts become payable. We recognize incentive management fees on a monthly basis over the term of the agreement based on each property’s financial results, as long as we do not expect a significant reversal due to projected future hotel performance or cash flows in future periods. Franchise Fee and Royalty Fee Revenue : For our franchised hotels, we have a performance obligation to provide franchisees and operators a license to our intellectual property for use of certain of our brand names. As compensation for such services, we are typically entitled to initial application fees and ongoing royalty fees. Our ongoing royalty fees represent variable consideration, as the transaction price is based on a percentage of certain revenues of the hotels, as defined in each contract. We recognize royalty fees on a monthly basis over the term of the agreement as those amounts become payable. Initial application and relicensing fees are fixed consideration payable upon submission of a franchise application or renewal and are recognized on a straight-line basis over the initial or renewal term of the franchise agreements. Owned and Leased Hotel Revenue : At our owned and leased hotels, we have performance obligations to provide accommodations and other ancillary services to hotel guests. As compensation for such goods and services, we are typically entitled to a fixed nightly fee for an agreed upon period and additional fixed fees for any ancillary services purchased. These fees are generally payable at the time the hotel guest checks out of the hotel. We generally satisfy the performance obligations over time, and we recognize the revenue from room sales and from other ancillary guest services on a daily basis, as the rooms are occupied and we have rendered the services. Cost Reimbursements : Under our management and franchise agreements, we are entitled to be reimbursed for certain costs we incur on behalf of the managed, franchised, and licensed properties, with no added mark-up. These costs primarily consist of payroll and related expenses at managed properties where we are the employer of the employees at the properties and include certain operational and administrative costs as provided for in our contracts with the owners. We are entitled to reimbursement in the period we incur the related reimbursable costs, which we recognize within the “Cost reimbursement revenue” caption of our Income Statements. Under our management and franchise agreements, hotel owners and franchisees participate in certain centralized programs and services, such as marketing, sales, reservations, and insurance programs. We operate these programs and services for the benefit of our hotel owners. We do not operate these programs and services to generate a profit over the long term, and accordingly, when we recover the costs that we incur for these programs and services from our hotel owners, we do not seek a mark-up. The amounts we charge for these programs and services are generally a combination of fixed fees and variable fees based on sales or other metrics and are payable on a monthly basis. We generally recognize revenue within the “Cost reimbursement revenue” caption of our Income Statements when the amounts may be billed to hotel owners, and we recognize expenses within the “Reimbursed expenses” caption as they are incurred. This pattern of recognition results in timing differences between the costs incurred for centralized programs and services and the related reimbursement from hotel owners in our operating and net income. Over the long term, these programs and services are not designed to impact our economics, either positively or negatively. In addition, we present in the “Reimbursed expenses” caption of our Income Statements spending funded by the proceeds ($664 million, $425 million after-tax) from the 2017 sale of our interest in Avendra LLC, which we committed would be used for the benefit of hotels in our system. Such spending totaled $62 million ($46 million after-tax) in 2020, $118 million ($87 million after-tax) in 2019, and $115 million ($85 million after-tax) in 2018. Other Revenue : Includes Global Design fees, which we describe below, termination fees, and other property and brand revenues. We generally recognize termination fees when collection is probable and other revenue as services are rendered. Amounts received in advance are deferred as liabilities. We provide hotel design and construction review quality assurance (“Global Design”) services to our managed and franchised hotel owners, generally during the period prior to a hotel’s opening or during the period a hotel is converting to a Marriott brand (the “pre-opening period”). As compensation for such services, we may be entitled to receive a one-time fixed fee that is payable during the pre-opening period of the hotel. As these services are not a distinct performance obligation, we recognize the fees on a straight-line basis over the initial term of the management or franchise agreement within the “Owned, leased, and other revenue” caption of our Income Statements. Practical Expedients and Exemptions : We do not disclose the amount of variable consideration that we expect to recognize in future periods in the following circumstances: (1) if we recognize the revenue based on the amount invoiced or services performed; (2) for sales-based or usage-based royalty promised in exchange for a license of intellectual property; or (3) if the consideration is allocated entirely to a wholly unsatisfied promise to transfer a distinct service that forms part of a single performance obligation, and the terms of the consideration relate specifically to our efforts to transfer, or to a specific outcome from transferring the service. We are required to collect certain taxes and fees from customers on behalf of governmental agencies and remit these to the applicable governmental agencies on a periodic basis. We do not include these taxes in determining the transaction price. Loyalty Program : Loyalty Program members earn points based on the money they spend at our hotels; purchases of timeshare interval, fractional ownership, and residential products; and through participation in travel experiences and affiliated partners’ programs, such as those offered by credit card, car rental, airline, and other companies. Members can redeem points, which we track on their behalf, for stays at most of our hotels, airline tickets, airline frequent flyer program miles, rental cars, and a variety of other awards. Points cannot be redeemed for cash. Under our Loyalty Program, we have a performance obligation to provide or arrange for the provision of goods or services for free or at a discount to Loyalty Program members in exchange for the redemption of points earned from past activities. We operate our Loyalty Program as a cross-brand marketing program to participating properties. Our management and franchise agreements require that properties reimburse us for a portion of the costs of operating the Loyalty Program, including costs for marketing, promotion, communication with, and performing member services for Loyalty Program members, with no added mark-up. We generally receive cash contributions on a monthly basis from managed, franchised, owned, and leased hotels based on a portion of qualified spend by Loyalty Program members (when the points are issued). We recognize these contributions into revenue as we provide the related service (when the points are redeemed). The amount of revenue we recognize upon point redemption is based on a blend of historical funding rates and is impacted by our estimate of the “breakage” for points that members will never redeem. We estimate breakage based on our historical experience and expectations of future member behavior. We recognize revenue net of the redemption cost within our “Cost reimbursement revenue” caption on our Income Statements, as our performance obligation is to facilitate the transaction between the Loyalty Program member and the managed or franchised property or program partner. Our redemption cost, which is generally based on redemption rates that can increase in periods in which occupancy at the property exceeds a certain threshold, could be higher or lower than our revenue recognized in any given period. We recognize all other Loyalty Program costs as incurred in our “Reimbursed expenses” caption. We have multi-year agreements for our co-brand credit cards associated with our Loyalty Program. Under these agreements, we have performance obligations to provide a license to the intellectual property associated with our brands and marketing lists (“Licensed IP”) to the financial institutions that issue the credit cards, to arrange for the redemption of Loyalty Program points as discussed in the preceding paragraph, and to arrange for the redemption of free night certificates provided to cardholders. We receive fees from these agreements, including fixed amounts that are primarily payable at contract inception, and variable amounts that are paid to us monthly over the term of the agreements, based on: (1) the number of free night certificates issued and redeemed; (2) the number of Loyalty Program points purchased; and (3) the volume of cardholder spend. We allocate those fees among the performance obligations, including the Licensed IP, our Loyalty Program points, and free night certificates provided to cardholders based on their estimated standalone selling prices. The estimation of the standalone selling prices requires significant judgments based upon generally accepted valuation methodologies regarding the value of our Licensed IP, the amount of funding we will receive, and the number of Loyalty Program points and free night certificates we will issue over the term of the agreements. We base our estimates of these amounts on our historical experience and expectation of future cardholder behavior. We recognize the portion of the Licensed IP revenue that meets the sales-based royalty criteria as the credit cards are used and the remaining portion of the Licensed IP revenue on a straight-line basis over the contract term. In our Income Statements, we primarily recognize Licensed IP revenue in the “Franchise fees” caption, and we recognize a portion in the “Cost reimbursement revenue” caption. We recognize the revenue related to the Loyalty Program points as discussed in the preceding paragraph. We recognize the revenue related to the free night certificates when the related service is provided. We recognize revenue net of the redemption cost, as our performance obligation is to facilitate the transaction between the Loyalty Program member and the managed or franchised property. Contract Balances : We generally receive payments from customers as we satisfy our performance obligations. We record a receivable when we have an unconditional right to receive payment and only the passage of time is required before payment is due. We record deferred revenue when we receive payment, or have the unconditional right to receive payment, in advance of the satisfaction of our performance obligations related to franchise application and relicensing fees, Global Design fees, credit card branding license fees, and our Loyalty Program. Current and noncurrent deferred revenue increased by $907 million, to $1,867 million at December 31, 2020 from $960 million at December 31, 2019, primarily as a result of amendments to the existing agreements for our U.S.-issued co-brand credit cards associated with our Loyalty Program, which we signed in May 2020. These amendments provided the Company with $920 million of cash from the prepayment of certain future revenues, the early payment of a previously committed signing bonus, and the pre-purchase of Marriott Bonvoy points and other consideration. We recorded the amount of cash received primarily in the deferred revenue caption, and the remainder in the liability for guest loyalty program captions, on our Balance Sheet. Our current and noncurrent Loyalty Program liability increased by $553 million, to $6,271 million at December 31, 2020, from $5,718 million at December 31, 2019, primarily reflecting an increase in points earned by members, partially offset by $1,118 million of revenue recognized in 2020, that was deferred as of December 31, 2019. The current portion of our Loyalty Program liability decreased compared to December 31, 2019, due to lower estimated redemptions in the short-term as a result of COVID-19. At each reporting period, we evaluate the estimates used in the recognition of Loyalty Program revenues, including estimates of the breakage of points that members will never redeem and the amount of funding we expect to receive over the life of the agreements with various third parties. In 2020, the updated estimates resulted in a net decrease in deferred revenue, and a corresponding ne t increase in rev enue of approximately $47 million. Costs Incurred to Obtain and Fulfill Contracts with Customers We incur certain costs to obtain and fulfill contracts with customers, which we capitalize and amortize on a straight-line basis over the initial, non-cancellable term of the contract. We classify incremental costs of obtaining a contract with a customer in the “Contract acquisition costs and other” caption of our Balance Sheets, the related amortization in the “Contract investment amortization” caption of our Income Statements, and the cash flow impact in the “Contract acquisition costs” caption of our Statements of Cash Flows. We assess the assets for impairment when events or changes in circumstances indicate that we may not be able to recover the carrying value. We recognize an impairment loss for the amount by which the carrying value exceeds the expected net future cash flows. We classify certain direct costs to fulfill a contract with a customer in the “Other noncurrent assets” and “Prepaid expenses and other” captions of our Balance Sheets, and the related amortization in the “Owned, leased, and other - direct expenses” caption of our Income Statements. We had capitalized costs to fulfill contracts with customers of $366 million at December 31, 2020 and $351 million at December 31, 2019. See Note 11 for information on capitalized costs incurred to obtain contracts with customers. Real Estate Sales We recognize a gain or loss on real estate transactions when control of the asset transfers to the buyer, generally at the time the sale closes. In sales transactions where we retain a management contract, the terms and conditions of the management contract are generally comparable to the terms and conditions of the management contracts obtained directly with third-party owners in competitive processes. Retirement Savings Plan We contribute to tax-qualified retirement plans for the benefit of U.S. employees who meet certain eligibility requirements and choose to participate in the plans. Participating employees specify the percentage or amount of salary they wish to contribute from their compensation, and the Company typically makes discretionary and certain other matching or supplemental contributions. We recognized compensation costs from Company contributions of $75 million in 2020, $128 million in 2019, and $224 million in 2018. Non-U.S. Operations The U.S. dollar is the functional currency of our consolidated and unconsolidated entities operating in the U.S. The functional currency of our consolidated and unconsolidated entities operating outside of the U.S. is generally the principal currency of the economic environment in which the entity primarily generates and expends cash. We translate the financial statements of consolidated entities whose functional currency is not the U.S. dollar into U.S. dollars, and we do the same, as needed, for unconsolidated entities whose functional currency is not the U.S. dollar. We translate assets and liabilities at the exchange rate in effect as of the financial statement date and translate income statement accounts using the weighted average exchange rate for the period. We include translation adjustments from currency exchange and the effect of exchange rate changes on intercompany transactions of a long-term investment nature as a separate component of stockholders’ equity. We report gains and losses from currency exchange rate changes for intercompany receivables and payables that are not of a long-term investment nature, as well as for third-party transactions, currently in operating costs and expenses. Stock-Based Compensation Our stock-based compensation awards primarily consist of restricted stock units (“RSUs”). We measure compensation costs for our stock-based payment transactions at fair value based on the closing stock price on the grant date, and we recognize those costs in our Financial Statements over the vesting period during which the employee provides service in exchange for the award. Advertising Costs We expense costs to produce advertising as they are incurred and to communicate advertising as the communication occurs and record such amounts in reimbursed expenses to the extent undertaken on behalf of our owners and franchisees. We recognized advertising costs of $276 million in 2020, $851 million in 2019, and $660 million in 2018. Income Taxes We record the amounts of taxes payable or refundable for the current year, as well as deferred tax liabilities and assets for the future tax consequences of events we have recognized in our Financial Statements or tax returns, using judgment in assessing future profitability and the likely future tax consequences of those events. We base our estimates of deferred tax assets and liabilities on current tax laws, rates and interpretations, and, in certain cases, business plans and other expectations about future outcomes. We develop our estimates of future profitability based on our historical data and experience, industry projections, micro and macro general economic condition projections, and our expectations. We account for U.S. tax on Global Intangible Low-Taxed Income in the period incurred. We generally recognize the effect of the tax law changes in the period of enactment. Changes in existing tax laws and rates, their related interpretations, and the uncertainty generated by the current economic environment may affect the amounts of our deferred tax liabilities or the valuations of our deferred tax assets over time. Our accounting for deferred tax consequences represents management’s best estimate of future events that can be appropriately reflected in the accounting estimates. For tax positions we have taken or expect to take in a tax return, we apply a more likely than not threshold (that is, a likelihood of more than 50 percent), under which we must conclude a tax position is more likely than not to be sustained, assuming that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information, to continue to recognize the benefit. In determining our provision for income taxes, we use judgment, reflecting our estimates and assumptions, in applying the more likely than not threshold. We recognize accrued interest and penalties for our unrecognized tax benefits as a component of tax expense. See Note 7 for further information. Cash and Equivalents We consider all highly liquid investments with an initial maturity of three months or less at date of purchase to be cash equivalents. Accounts Receivable Our accounts receivable primarily consist of amounts due from hotel owners with whom we have management and franchise agreements and include reimbursements of costs we incurred on behalf of managed and franchised properties. We record an allowance for credit losses measured over the contractual life of the instrument based on an assessment of historical collection activity and current and forecasted future economic conditions by region. Assets Held for Sale We consider properties to be assets held for sale when (1) management commits to a plan to sell the property; (2) it is unlikely that the disposal plan will be significantly modified or discontinued; (3) the property is available for immediate sale in its present condition; (4) actions required to complete the sale of the property have been initiated; (5) sale of the property is probable and we expect the completed sale will occur within one year; and (6) the property is actively being marketed for sale at a price that is reasonable given our estimate of current market value. Upon designation of a property as an asset held for sale, we record the property’s value at the lower of its carrying value or its estimated fair value, less estimated costs to sell, and we cease depreciation. Goodwill We test goodwill for potential impairment at least annually in the fourth quarter, or more frequently if an event or other circumstance indicates that we may not be able to recover the carrying amount of the net assets of the reporting unit. In evaluating goodwill for impairment, we may assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If we bypass the qualitative assessment, or if we conclude that it is more likely than not that the fair value of a reporting unit is less than its carrying value, then we perform a quantitative impairment test by comparing the fair value of a reporting unit with its carrying amount. We calculate the estimated fair value of a reporting unit using a combination of the income and market approaches. For the income approach, we use internally developed discounted cash flow models that include the following assumptions, among others: projections of revenues, expenses, and related cash flows based on assumed long-term growth rates and demand trends; expected future investments to grow new units; and estimated discount rates. For the market approach, we use internal analyses based primarily on market comparables. We base these assumptions on our historical data and experience, third-party appraisals, industry projections, micro and macro general economic condition projections, and our expectations. We have had no goodwill impairment charges for the last three fiscal years. Intangibles and Long-Lived Assets We assess indefinite-lived intangible assets for continued indefinite use and for potential impairment annually, or more frequently if an event or other circumstance indicates that we may not be able to recover the carrying amount of the asset. Like goodwill, we may first assess qualitative factors to determine whether it is more likely than not that the fair value of the indefinite-lived intangible is less than its carrying amount. If the carrying value of the asset exceeds the fair value, we recognize an impairment loss in the amount of that excess. We test definite-lived intangibles and long-lived asset groups for recoverability when changes in circumstances indicate that we may not be able to recover the carrying value; for example, when there are material adverse changes in projected revenues or expenses, significant underperformance relative to historical or projected operating results, or significant negative industry or economic trends. We also test recoverability when management has committed to a plan to sell or otherwise dispose of an asset group and we expect to complete the plan within a year. We evaluate recoverability of an asset group by comparing its carrying value, including right-of-use assets, to the future net undiscounted cash flows that we expect the asset group will generate. If the comparison indicates that we will not be able to recover the carrying value of an asset group, we recognize an impairment loss for the amount by which the carrying value exceeds the estimated fair value. When we recognize an impairment loss for assets to be held and used, we depreciate the adjusted carrying amount of those assets over their remaining useful life. We calculate the estimated fair value of an intangible asset or asset group using the income approach or the market approach. We utilize the same assumptions and methodology for the income approach that we describe in the “ Goodwill ” caption. For the market approach, we use internal analyses based primarily on market comparables and assumptions about market capitalization rates, growth rates, and inflation. See Note 9 and Note 12 for additional information. Investments We hold equity interests in ventures established to develop or acquire and own hotel properties or that otherwise support our hospitality operations. We account for these investments as either an equity method investment, a financial asset, or a controlled subsidiary. We apply the equity method of accounting if we have significant influence over the entity, typically when we hold 20 percent or more of the voting common stock (or equivalent) of an investee but do not have a controlling financial interest. In certain circumstances, such as with investments in limited liability companies or limited partnerships, we apply the equity method of accounting when we own as little as three to five percent. We account for financial assets at fair value if it is readily determinable, or using the fair value alternative method, whereby investments are measured at cost less impairment, adjusted for observable price changes. We consolidate entities that we control. When we acquire an investment that qualifies for the equity method of accounting, we determine the acquisition date fair value of the identifiable assets and liabilities. If our carrying amount exceeds our proportional share in the equity of the investee, we amortize the difference on a straight-line basis over the underlying assets’ estimated useful lives when calculating equity method earnings attributable to us, excluding the difference attributable to land, which we do not amortize. We evaluate an investment for impairment when circumstances indicate that we may not be able to recover the carrying value. When evaluating our ventures, we consider loan defaults, significant underperformance relative to historical or projected operating performance, or significant negative industry or economic trends. Additionally, a venture’s commitment to a plan to sell some or all of its assets could cause us to evaluate the recoverability of the venture’s individual long-lived assets and possibly the venture itself. We impair investments we account for using the equity method of accounting when we determine that there has been an “other-than-temporary” decline in the venture’s estimated fair value compared to its carrying value. We perform qualitative assessments for investments we account for using the fair value alternative method and we record any associated impairment when the fair value is less than the carrying value. Under the accounting guidance for the consolidation of variable interest entities, we analyze our variable interests, including equity investments, loans, and guarantees, to determine if an entity in which we have a variable interest is a variable interest entity. Our analysis includes both quantitative and qualitative reviews. We base our quantitative analysis on the forecasted cash flows of the entity, and our qualitative analysis on our review of the design of the entity, its organizational structure including decision-making ability, and relevant financial agreements. We also use our qualitative analysis to determine if we must consolidate a variable interest entity as its primary beneficiary. Fair Value Measurements We have various financial instruments we must measure at fair value on a recurring basis, including certain marketable securities and derivatives. See Note 13 for further information. We also apply the provisions of fair value measurement to various nonrecurring measurements for our financial and nonfinancial assets and liabilities. Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). We measure our assets and liabilities using inputs from the following three levels of the fair value hierarchy: Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). Level 3 includes unobservable inputs that reflect our assumptions about what factors market participants would use in pricing the asset or liability. We develop these inputs based on the best information available, including our own data. Derivative Instruments We record derivatives at fair value. The designation of a derivative instrument as a hedge and its ability to meet the hedge accounting criteria determine how we reflect the change in fair value of the derivative instrument in our Financial Statements. A derivative qualifies for hedge accounting if, at inception, we expect the derivative will be highly effective in offsetting the underlying hedged cash flows or fair value and we fulfill the hedge documentation standards at the time we enter into the derivative contract. We designate a hedge as a cash flow hedge, fair value hedge, or a hedge of the net investment in non-U.S. operations based on the exposure we are hedging. For the effective portion of qualifying cash flow hedges, we record changes in fair value in accumulated other comprehensive income (“AOCI”). We release the derivative’s gain or loss from AOCI to match the timing of the underlying hedged items’ effect on earnings. The change in fair value of qualifying fair value hedges as well as changes in fair value of the underlying hedged items to the hedged risks are recorded concurrently in earnings. We review the effectiveness of our hedging instruments quarterly and discontinue hedge accounting for any hedge that we no longer consider to be highly effective. We recognize changes in fair value for derivatives not designated as hedges or those not qualifying for hedge accounting in current period earnings. Upon termination of cash flow hedges, we release gains and losses from AOCI based on the timing of the underlying cash flows or revenue recognized, unless the termination results from the failure of the intended transaction to occur in the expected time frame. Such untimely transactions require us to immediately recognize in earnings the gains and/or losses that we previously recorded in AOCI. Changes in interest rates, currency exchange rates, and equity securities expose us to market risk. We manage our exposure to these risks by monitoring available financing alternatives, as well as through development and application of credit granting policies. We also use derivative instruments as part of our overall strategy to manage our exposure to market risks. As a matter of policy, we only enter into transactions that we believe will be highly effective at offsetting the underlying risk, and we do not use derivatives for trading or speculative purposes. Loan Loss Reserves We may make senior, mezzanine, and other loans to owners of hotels that we operate or franchise, generally to facilitate the development of a hotel and sometimes to facilitate brand programs or initiatives. We expect the owners to repay the loans in accordance with the loan agreements, or earlier as the hotels mature and capital markets permit. We use metrics such as loan-to-value ratios and

RESTRUCTURING CHARGES

RESTRUCTURING CHARGES	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
RESTRUCTURING CHARGES	RESTRUCTURING CHARGES Beginning in the 2020 second quarter, we initiated several regional restructuring plans to achieve cost savings in response to the decline in lodging demand caused by COVID-19. In 2020, we recorded $366 million of restructuring charges for above-property, property-level, and owned and leased properties employee termination benefits, of which we present $56 million in the “Restructuring and merger-related charges” caption and $310 million in the “Reimbursed expenses” caption of our Income Statements. Our U.S. & Canada segment recorded $255 million of the total restructuring charges in 2020. In 2020, we recorded $117 million of global above-property restructuring charges, of which we present $44 million in the “Restructuring and merger-related charges” caption and $73 million in the “Reimbursed expenses” caption of our Income Statements. We have substantially completed the programs relating to our above-property organization as of year-end 2020. In 2020, we recorded $249 million of property-level and owned and leased properties restructuring charges, of which we present $12 million in the “Restructuring and merger-related charges” caption and $237 million in the “Reimbursed expenses” caption of our Income Statements. We anticipate additional property-level and owned and leased properties restructuring charges in future quarters. The following table presents our restructuring reserve activity during the period: ($ in millions) Employee termination benefits Balance at December 31, 2019 $ — Charges 366 Cash payments (215) Other (8) Balance at December 31, 2020, classified in “Accrued expenses and other” $ 143

DISPOSITIONS AND ACQUISITIONS

DISPOSITIONS AND ACQUISITIONS	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
DISPOSITIONS AND ACQUISITIONS	DISPOSITIONS AND ACQUISITIONS Dispositions In 2020, we sold one U.S. & Canada property for $268 million. We continue to operate the hotel under a long-term management agreement. In 2019, we sold two U.S. & Canada properties and recognized total gains of $134 million in the “Gains and other income, net” caption of our Income Statements. We continue to operate the hotels under long-term management agreements. In 2018, we sold two U.S. & Canada properties, two Asia Pacific properties, and two Caribbean and Latin America properties and recognized total gains of $132 million in the “Gains and other income, net” caption of our Income Statements. We continue to operate all but one of these hotels under long-term management agreements. In 2018, we sold our interest in three equity method investments, whose assets included a plot of land in Italy, a Caribbean and Latin America property, and an Asia Pacific property, and we recognized total gains of $42 million in the “Gains and other income, net” caption of our Income Statements. Also, in 2018, third-party investees sold a Caribbean and Latin America property and a U.S. & Canada property, and we recorded our share of the gains of $55 million and $10 million, respectively, in the “Equity in (losses) earnings” caption of our Income Statements. Acquisitions In 2019, we completed the acquisition of Elegant Hotels Group plc (“Elegant”) for $128 million in cash and assumed Elegant’s net debt outstanding of $63 million, which we subsequently repaid in January 2020. As a result of the transaction, we added seven hotels and a beachfront restaurant on the island of Barbados to our Caribbean and Latin America owned and leased portfolio. In 2019, we purchased a U.S. & Canada property for $206 million.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The table below illustrates the reconciliation of the earnings and number of shares used in our calculations of basic and diluted earnings per share, the latter of which uses the treasury stock method in order to calculate the dilutive effect of the Company’s potential common stock: (in millions, except per share amounts) 2020 2019 2018 Computation of Basic (Loss) Earnings Per Share Net (loss) income $ (267) $ 1,273 $ 1,907 Shares for basic (loss) earnings per share 325.8 332.7 350.1 Basic (loss) earnings per share $ (0.82) $ 3.83 $ 5.45 Computation of Diluted (Loss) Earnings Per Share Net (loss) income $ (267) $ 1,273 $ 1,907 Shares for basic earnings per share 325.8 332.7 350.1 Effect of dilutive securities Stock-based compensation (1) — 2.8 4.1 Shares for diluted (loss) earnings per share 325.8 335.5 354.2 Diluted (loss) earnings per share $ (0.82) $ 3.80 $ 5.38 (1) For the calculation of diluted loss per share for year-end 2020, we excluded share-based compensation securities of 1.4 million because the effect was anti-dilutive.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION RSUs and PSUs We granted RSUs in the 2020 first quarter to certain officers and key employees, and those units vest generally over four years in equal annual installments commencing one year after the grant date. We also granted performance-based RSUs (“PSUs”) in the 2020 first quarter to certain executive officers, which are earned, subject to continued employment and the satisfaction of certain performance conditions based on achievement of pre-established targets for gross room openings, active Marriott Bonvoy loyalty member growth, and adjusted operating income growth over, or at the end of, a three We had deferred compensation costs for RSUs of approximately $301 million at year-end 2020 and $176 million at year-end 2019. The weighted average remaining term for RSUs outstanding at year-end 2020 was 2.5 years. The following table provides additional information on RSUs, including PSUs, for the last three fiscal years: 2020 2019 2018 Stock-based compensation expense (in millions) $ 188 $ 177 $ 170 Weighted average grant-date fair value (per RSU) $ 101 $ 117 $ 132 Aggregate intrinsic value of distributed RSUs (in millions) $ 234 $ 276 $ 294 The following table presents the changes in our outstanding RSUs, including PSUs, during 2020 and the associated weighted average grant-date fair values: Number of RSUs (in millions) Weighted Average Grant-Date Fair Value (per unit) Outstanding at year-end 2019 4.1 $ 106 Granted 3.6 101 Distributed (1.6) 97 Forfeited (0.3) 114 Outstanding at year-end 2020 5.8 $ 107 Other Information At year-end 2020, we had 27 million remaining shares authorized under the Marriott and Starwood Hotels & Resorts Worldwide, LLC, formerly known as Starwood Hotels & Resorts Worldwide, Inc. (“Starwood”) stock plans.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The components of our (losses) earnings before income taxes for the last three fiscal years consisted of: ($ in millions) 2020 2019 2018 U.S. $ (320) $ 549 $ 1,311 Non-U.S. (146) 1,050 1,034 $ (466) $ 1,599 $ 2,345 Our benefit (provision) for income taxes for the last three fiscal years consisted of: ($ in millions) 2020 2019 2018 Current -U.S. Federal $ 9 $ (272) $ (169) -U.S. State (41) (57) (94) -Non-U.S. (78) (161) (284) (110) (490) (547) Deferred -U.S. Federal 180 141 10 -U.S. State 81 39 (6) -Non-U.S. 48 (16) 105 309 164 109 $ 199 $ (326) $ (438) Unrecognized Tax Benefits The following table reconciles our unrecognized tax benefit balance for each year from the beginning of 2018 to the end of 2020: ($ in millions) Amount Unrecognized tax benefit at beginning of 2018 $ 491 Change attributable to tax positions taken in prior years 37 Change attributable to tax positions taken during the current period 148 Decrease attributable to settlements with taxing authorities (53) Unrecognized tax benefit at year-end 2018 623 Change attributable to tax positions taken in prior years (13) Change attributable to tax positions taken during the current period 13 Decrease attributable to settlements with taxing authorities (54) Unrecognized tax benefit at year-end 2019 569 Change attributable to tax positions taken in prior years (66) Change attributable to tax positions taken during the current period 4 Decrease attributable to settlements with taxing authorities (43) Unrecognized tax benefit at year-end 2020 $ 464 Our unrecognized tax benefit balances included $410 million at year-end 2020, $498 million at year-end 2019, and $497 million at year-end 2018 of tax positions that, if recognized, would impact our effective tax rate. It is reasonably possible that within the next twelve months we will reach resolution of income tax examinations in one or more jurisdictions. The actual amount of any change to our unrecognized tax benefits could vary depending on the timing and nature of the settlement. Therefore, an estimate of the change cannot be provided. We recognize accrued interest and penalties for our unrecognized tax benefits as a component of tax expense. Related interest (benefit) expense totaled $(15) million in 2020, $28 million in 2019, and $3 million in 2018. We accrued interest and penalties related to our unrecognized tax benefits of approximately $85 million at year-end 2020 and $100 million at year-end 2019 on our Balance Sheets. We file income tax returns, including returns for our subsidiaries, in various jurisdictions around the world. The U.S. Internal Revenue Service (“IRS”) has examined our federal income tax returns, and as of year-end 2020, we have settled all issues for tax years through 2013 for Marriott and through 2012 for Starwood. Our Marriott 2014 and 2015 tax year audits are substantially complete, and our Marriott 2016 through 2018 tax year audits are currently ongoing. Starwood is currently under audit by the IRS for years 2013 through 2016. Various foreign, state, and local income tax returns are also under examination by the applicable taxing authorities. Deferred Income Taxes Deferred income tax balances reflect the effects of temporary differences between the carrying amounts of assets and liabilities and their tax bases, as well as from net operating loss and tax credit carry-forwards. We state those balances at the enacted tax rates we expect will be in effect when we pay or recover the taxes. Deferred income tax assets represent amounts available to reduce income taxes we will pay on taxable income in future years. We evaluate our ability to realize these future tax deductions and credits by assessing whether we expect to have sufficient future taxable income from all sources, including reversal of taxable temporary differences, forecasted operating earnings, and available tax planning strategies to utilize these future deductions and credits. We establish a valuation allowance when we no longer consider it more likely than not that a deferred tax asset will be realized. The following table presents the tax effect of each type of temporary difference and carry-forward that gave rise to significant portions of our deferred tax assets and liabilities as of year-end 2020 and year-end 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Deferred Tax Assets Employee benefits $ 262 $ 267 Net operating loss carry-forwards 818 680 Accrued expenses and other reserves 214 162 Receivables, net 12 11 Tax credits 49 41 Loyalty Program 367 249 Deferred income 69 70 Lease liabilities 252 261 Other 82 15 Deferred tax assets 2,125 1,756 Valuation allowance (1,009) (616) Deferred tax assets after valuation allowance 1,116 1,140 Deferred Tax Liabilities Equity method investments (29) (55) Property and equipment (42) (82) Intangibles (663) (895) Right-of-use assets (197) (229) Self-insurance (19) (15) Deferred tax liabilities (950) (1,276) Net deferred taxes $ 166 $ (136) Our valuation allowance is attributable to non-U.S. and U.S. state net operating loss carry-forwards. During 2020, our valuation allowance increased primarily due to legislative changes in Switzerland and net operating losses in Luxembourg. At year-end 2020, we had approximately $31 million of tax credits that will expire through 2030 and $17 million of tax credits that do not expire. We recorded $44 million of net operating loss benefits in 2020 and $10 million in 2019. At year-end 2020, we had approximately $3,938 million of primarily state and foreign net operating losses, of which $2,315 million will expire through 2040. We made no provision for U.S. income taxes or additional non-U.S. taxes on certain undistributed earnings of non-U.S. subsidiaries. These earnings could become subject to additional taxes if the non-U.S. subsidiaries dividend or loan those earnings to an affiliate or if we sell our interests in the non-U.S. subsidiaries. We cannot practically estimate the amount of additional taxes that might be payable on the undistributed earnings. Reconciliation of U.S. Federal Statutory Income Tax Rate to Actual Income Tax Rate The following table reconciles the U.S. statutory tax rate to our effective income tax rate for the last three fiscal years: 2020 2019 2018 U.S. statutory tax rate 21.0 % 21.0 % 21.0 % U.S. state income taxes, net of U.S. federal tax benefit 3.8 1.6 2.5 Non-U.S. income 12.5 (3.3) (1.0) Change in valuation allowance (20.0) 3.4 2.6 Change in uncertain tax positions 12.2 1.9 1.0 Change in U.S. tax rate 0.0 0.0 (1.7) Permanent items 9.4 1.3 0.0 Tax on asset dispositions 0.0 (0.7) (2.9) Excess tax benefits related to equity awards 6.4 (3.2) (1.8) U.S. tax on foreign earnings (3.0) 0.1 0.0 Other, net 0.6 (1.7) (1.0) Effective rate 42.9 % 20.4 % 18.7 % The non-U.S. income tax benefit presented in the table above includes tax-exempt income in Hong Kong and Singapore, and a deemed interest deduction in Switzerland, which collectively represented 12.9% in 2020, 8.8% in 2019, and 4.0% in 2018. We included the impact of these items in the non-U.S. income line above because we consider them to be equivalent to a reduction of the statutory tax rates in these jurisdictions. Pre-tax income in Switzerland, Singapore, and Hong Kong totaled $314 million in 2020, $709 million in 2019, and $513 million in 2018. The non-U.S. income tax benefit also includes U.S. income tax expense on non-U.S. operations, which represents 0.8% in 2020, 2.0% in 2019, and 1.4% in 2018. We included the impact of this tax in the non-U.S. income line above because we consider this tax to be an integral part of the foreign taxes. Other Information

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Guarantees We issue guarantees to certain lenders and hotel owners, chiefly to obtain long-term management and franchise contracts. The guarantees generally have a stated maximum funding amount and a term of three We present the maximum potential amount of our future guarantee fundings and the carrying amount of our liability for our debt service, operating profit, and other guarantees (excluding contingent purchase obligations) for which we are the primary obligor at year-end 2020 in the following table: ($ in millions) Guarantee Type Maximum Potential Recorded Liability for Debt service $ 53 $ 6 Operating profit 207 128 Other 19 4 $ 279 $ 138 Our liability at year-end 2020 for guarantees for which we are the primary obligor is reflected in our Balance Sheets as $16 million of “Accrued expenses and other” and $122 million of “Other noncurrent liabilities.” Our maximum potential guarantees listed in the preceding table include $90 million of operating profit guarantees and $7 million of other guarantees that will not be in effect until the underlying properties open and we begin to operate the properties or certain other events occur. In conjunction with financing obtained for specific projects or properties owned by us or entities in which we have an investment, we may provide industry standard indemnifications to the lender for loss, liability, or damage occurring as a result of the actions of the entity or our own actions. Contingent Purchase Obligation Sheraton Grand Chicago . In 2017, we granted the owner a one-time right, exercisable in 2022, to require us to purchase the leasehold interest in the land and the hotel for $300 million in cash (the “put option”). If the owner exercises the put option, we have the option to purchase, at the same time the put transaction closes, the fee simple interest in the underlying land for an additional $200 million in cash. We account for the put option as a guarantee. In the 2020 fourth quarter, we estimated that the put option is probable of being exercised under the terms of the agreement, and accordingly, we increased our recorded liability from $57 million at year-end 2019 to $300 million at year-end 2020. We recorded the related expense in the “Restructuring and merger-related charges” caption of our Income Statements. We concluded that the entity that owns the Sheraton Grand Chicago hotel is a variable interest entity. We did not consolidate the entity because we do not have the power to direct the activities that most significantly impact the entity’s economic performance. Our maximum exposure to loss related to the entity is equal to the difference between the purchase price and the fair value of the hotel at the time that the put option is exercised, plus the maximum funding amount of an operating profit guarantee that we provided for the hotel. Commitments At year-end 2020, we had various purchase commitments for goods and services in the normal course of business, primarily for programs and services for which we are reimbursed by third-party owners, totaling $437 million. We expect to purchase goods and services subject to these commitments as follows: $186 million in 2021, $137 million in 2022, $48 million in 2023, and $66 million thereafter. Letters of Credit At year-end 2020, we had $156 million of letters of credit outstanding (all outside the Credit Facility, as defined in Note 10), most of which were for our self-insurance programs. Surety bonds issued as of year-end 2020 totaled $163 million, most of which state governments requested in connection with our self-insurance programs. Starwood Data Security Incident Description of Event On November 30, 2018, we announced a data security incident involving unauthorized access to the Starwood reservations database (the “Data Security Incident”). Working with leading security experts, we determined that there was unauthorized access to the Starwood network since 2014 and that an unauthorized party had copied information from the Starwood reservations database and taken steps towards removing it. The Starwood reservations database is no longer used for business operations . Expenses and Insurance Recoveries In 2020, we recorded an $11 million net reversal of expenses and $29 million of accrued insurance recoveries related to the Data Security Incident; in 2019, we recorded $148 million of expenses and $84 million of accrued insurance recoveries related to the Data Security Incident; and in 2018, we recorded $28 million of expenses and $25 million of accrued insurance recoveries related to the Data Security Incident. We received insurance recoveries of $47 million in 2020 and $58 million in 2019. The net reversal of expenses for 2020 is primarily due to the reduction of the accrual for the ICO fine to reflect the amount of the final ICO fine, as further described below. We recognize insurance recoveries when they are probable of receipt and present them in our Income Statements in the same caption as the related expense, up to the amount of total expense incurred in prior and current periods. We present expenses and insurance recoveries related to the Data Security Incident in either the “Reimbursed expenses” or “Restructuring and merger-related charges” captions of our Income Statements. Litigation, Claims, and Government Investigations Following our announcement of the Data Security Incident, approximately 100 lawsuits were filed by consumers and others against us in U.S. federal, U.S. state and Canadian courts related to the incident. All but one of the U.S. cases were consolidated and transferred to the U.S. District Court for the District of Maryland, pursuant to orders of the U.S. Judicial Panel on Multidistrict Litigation (the “MDL”). The plaintiffs in th e U.S. and Canadian cases, who generally purport to represent various classes of consumers, generally claim to have been harmed by alleged actions and/or omissions by the Company in connection with the Data Security Incident and assert a variety of common law and statutory claims seeking monetary damages, injunctive relief, costs and attorneys’ fees, and other related relief. Among the U.S. cases consolidated in the MDL proceeding is a putative class action lawsuit that was filed against us and certain of our current officers and directors on December 1, 2018, alleging violations of the federal securities laws in connection with statements regarding our cybersecurity systems and controls, and seeking certification of a class of affected persons, unspecified monetary damages, costs and attorneys’ fees, and other related relief. The MDL proceeding also includes two shareholder derivative complaints that were filed on February 26, 2019 and March 15, 2019, respectively, against the Company, certain of its officers and certain current and former members of our Board of Directors, alleging, among other claims, breach of fiduciary duty, corporate waste, unjust enrichment, mismanagement and violations of the federal securities laws, and seeking unspecified monetary damages and restitution, changes to the Company’s corporate governance and internal procedures, costs and attorneys’ fees, and other related relief. A separate shareholder derivative complaint was filed in the Delaware Court of Chancery on December 3, 2019 against the Company and certain of its officers and certain current and former members of our Board of Directors, alleging claims and seeking relief generally similar to the claims made and relief sought in the other two derivative cases. This case will not be consolidated with the MDL proceeding. We dispute the allegations in the lawsuits described above and are vigorously defending against such claims. We have filed motions to dismiss in each of these cases, some of which have been denied, but the cases generally remain at an early stage. The Canadian cases have effectively been consolidated into a single case in the province of Ontario. In April 2019, we received a letter purportedly on behalf of a stockholder of the Company (also one of the named plaintiffs in the putative securities class action described above) demanding that our Board of Directors take action against the Company’s current and certain former officers and directors to recover damages for alleged breaches of fiduciary duties and related claims arising from the Data Security Incident. The Board of Directors has constituted a demand review committee to investigate the claims made in the demand letter, and the committee has retained independent counsel to assist with the investigation. The committee’s investigation is ongoing. In addition, on August 18, 2020, a purported representative action was brought against us in the High Court of Justice for England and Wales on behalf of an alleged claimant class of English and Welsh residents alleging breaches of the General Data Protection Regulation and/or the U.K. Data Protection Act 2018 (the “U.K. DPA”) in connection with the Data Security Incident. We dispute all of the allegations in this purported action and will vigorously defend against any such claims. On November 5, 2020, the court issued an order with the consent of all parties staying this action pending resolution of another case raising similar issues, but not involving the Company, that is pending before the U.K. Supreme Court. In addition, numerous U.S. federal, U.S. state and foreign governmental authorities made inquiries, opened investigations, or requested information and/or documents related to the Data Security Incident and related matters, including Attorneys General offices from all 50 states and the District of Columbia, the Federal Trade Commission, the Securities and Exchange Commission, certain committees of the U.S. Senate and House of Representatives, the Information Commissioner’s Office in the United Kingdom (the “ICO”) as lead supervisory authority in the European Economic Area, and regulatory authorities in various other jurisdictions. With the exception of the ICO proceeding, these matters generally remain open. In July 2019, the ICO issued a formal notice of intent under the U.K. DPA proposing a fine in the amount of £99 million against the Company in relation to the Data Security Incident. We submitted written responses to the ICO vigorously defending our position and engaged with the ICO regarding the Data Security Incident and proposed fine. In October 2020, the ICO issued a final decision under the U.K. DPA, which includes a fine of £18.4 million. The Company did not appeal the ICO’s decision, but has made no admission of liability in relation to the decision or the underlying allegations. In 2019, we expensed $65 million for this loss contingency, in the “Restructuring and merger-related charges” caption of our Income Statements, based on the fine initially proposed by the ICO in July 2019 and the ongoing proceeding. In 2020, we recorded a $39 million reversal of expense, based on the ICO’s issuance of the final decision. We paid a portion of the ICO fine in the 2020 fourth quarter, and the remainder is payable over the next two years. Our accrual for this loss contingency, which we present in the “Accrued expenses and other” and “Other noncurrent liabilities” captions of our Balance Sheets, was $65 million at year-end 2019 and $17 million at year-end 2020. Our production of information and/or documents to the state Attorneys General and the Federal Trade Commission is now complete, and we are in the early stages of discussions with those authorities to resolve their investigations and requests. While we believe it is reasonably possible that we may incur additional losses associated with the above described proceedings and investigations related to the Data Security Incident, it is not possible to estimate the amount of loss or range of loss, if any, in excess of the amounts already incurred that might result from adverse judgments, settlements, fines, penalties or other resolution of these proceedings and investigations based on the current stage of these proceedings and investigations, the

LEASES

LEASES	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
LEASES	LEASES We enter into operating and finance leases primarily for hotels, offices, and equipment. Most leases have initial terms of up to 20 years, and contain one or more renewals at our option, generally for five The following table details the composition of lease expense for 2020 and 2019: ($ in millions) 2020 2019 Operating lease cost $ 157 $ 185 Variable lease cost 60 113 We recorded impairment charges of $116 million in 2020 and $99 million in 2019 in the “Depreciation, amortization, and other” caption of our Income Statements to reduce the carrying amount of certain U.S. & Canada hotel leases right-of-use assets and property and equipment, including leasehold improvements. The impairment charges recorded in 2020 were due to the impact of COVID-19. We determined that we may not be able to fully recover the carrying amount of these U.S. & Canada hotel leases after evaluating the assets for recovery due to declines in market performance and future cash flow projections. We estimated the fair value using an income approach reflecting internally developed Level 3 discounted cash flows that included, among other things, our expectations of future cash flows based on historical experience and projected growth rates, usage estimates and demand trends. Additionally, during the year ended 2019, we recorded expense of $34 million in the “Restructuring and merger-related charges” caption of our Income Statements due to the impairment of a legacy-Starwood office building accounted for as a finance lease. The following table presents our future minimum lease payments at year-end 2020: ($ in millions) Operating Leases Finance Leases 2021 $ 184 $ 13 2022 176 13 2023 124 14 2024 116 14 2025 106 14 Thereafter 529 138 Total minimum lease payments $ 1,235 $ 206 Less: Amount representing interest 265 53 Present value of minimum lease payments $ 970 $ 153 The following table presents the composition of our current and noncurrent lease liability at year-end 2020 and 2019: ($ in millions) December 31, 2020 December 31, 2019 Operating Leases Finance Leases Operating Leases Finance Leases Current (1) $ 147 $ 7 $ 130 $ 6 Noncurrent (2) 823 146 882 151 $ 970 $ 153 $ 1,012 $ 157 (1) Operating leases are recorded in the “ Accrued expenses and other (2) Operating leases are recorded in the “Operating lease liabilities” and finance leases are recorded in the “Long-term debt” captions of our Balance Sheets. At year-end 2020, we had entered into an agreement that we expect to account for as an operating lease with a 20-year term for our new headquarters office, which is not reflected in our Balance Sheets or in the table above as the lease has not commenced. The following table presents additional information about our lease obligations at year-end 2020 and 2019: 2020 2019 Operating leases Finance leases Operating leases Finance leases Weighted Average Remaining Lease Term (in years) 10 13 11 14 Weighted Average Discount Rate 4.6 % 4.4 % 4.8 % 4.4 % The following table presents supplemental cash flow information for 2020 and 2019: ($ in millions) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows for operating leases $ 162 $ 176 Operating cash outflows for finance leases 7 7 Financing cash outflows for finance leases 6 6 Lease assets obtained in exchange for lease obligations: Operating leases 35 89
LEASES	LEASES We enter into operating and finance leases primarily for hotels, offices, and equipment. Most leases have initial terms of up to 20 years, and contain one or more renewals at our option, generally for five The following table details the composition of lease expense for 2020 and 2019: ($ in millions) 2020 2019 Operating lease cost $ 157 $ 185 Variable lease cost 60 113 We recorded impairment charges of $116 million in 2020 and $99 million in 2019 in the “Depreciation, amortization, and other” caption of our Income Statements to reduce the carrying amount of certain U.S. & Canada hotel leases right-of-use assets and property and equipment, including leasehold improvements. The impairment charges recorded in 2020 were due to the impact of COVID-19. We determined that we may not be able to fully recover the carrying amount of these U.S. & Canada hotel leases after evaluating the assets for recovery due to declines in market performance and future cash flow projections. We estimated the fair value using an income approach reflecting internally developed Level 3 discounted cash flows that included, among other things, our expectations of future cash flows based on historical experience and projected growth rates, usage estimates and demand trends. Additionally, during the year ended 2019, we recorded expense of $34 million in the “Restructuring and merger-related charges” caption of our Income Statements due to the impairment of a legacy-Starwood office building accounted for as a finance lease. The following table presents our future minimum lease payments at year-end 2020: ($ in millions) Operating Leases Finance Leases 2021 $ 184 $ 13 2022 176 13 2023 124 14 2024 116 14 2025 106 14 Thereafter 529 138 Total minimum lease payments $ 1,235 $ 206 Less: Amount representing interest 265 53 Present value of minimum lease payments $ 970 $ 153 The following table presents the composition of our current and noncurrent lease liability at year-end 2020 and 2019: ($ in millions) December 31, 2020 December 31, 2019 Operating Leases Finance Leases Operating Leases Finance Leases Current (1) $ 147 $ 7 $ 130 $ 6 Noncurrent (2) 823 146 882 151 $ 970 $ 153 $ 1,012 $ 157 (1) Operating leases are recorded in the “ Accrued expenses and other (2) Operating leases are recorded in the “Operating lease liabilities” and finance leases are recorded in the “Long-term debt” captions of our Balance Sheets. At year-end 2020, we had entered into an agreement that we expect to account for as an operating lease with a 20-year term for our new headquarters office, which is not reflected in our Balance Sheets or in the table above as the lease has not commenced. The following table presents additional information about our lease obligations at year-end 2020 and 2019: 2020 2019 Operating leases Finance leases Operating leases Finance leases Weighted Average Remaining Lease Term (in years) 10 13 11 14 Weighted Average Discount Rate 4.6 % 4.4 % 4.8 % 4.4 % The following table presents supplemental cash flow information for 2020 and 2019: ($ in millions) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows for operating leases $ 162 $ 176 Operating cash outflows for finance leases 7 7 Financing cash outflows for finance leases 6 6 Lease assets obtained in exchange for lease obligations: Operating leases 35 89

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT We provide detail on our long-term debt balances, net of discounts, premiums, and debt issuance costs, in the following table at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Senior Notes: Series L Notes, interest rate of 3.3%, face amount of $173, maturing September 15, 2022 (effective interest rate of 3.4%) $ 173 $ 349 Series M Notes, interest rate of 3.4%, face amount of $350, matured October 15, 2020 (effective interest rate of 3.6%) — 349 Series N Notes, interest rate of 3.1%, face amount of $400, maturing October 15, 2021 (effective interest rate of 3.4%) 399 398 Series O Notes, interest rate of 2.9%, face amount of $450, maturing March 1, 2021 (effective interest rate of 3.1%) 450 449 Series P Notes, interest rate of 3.8%, face amount of $350, maturing October 1, 2025 (effective interest rate of 4.0%) 346 346 Series Q Notes, interest rate of 2.3%, face amount of $399, maturing January 15, 2022 (effective interest rate of 2.5%) 398 747 Series R Notes, interest rate of 3.1%, face amount of $750, maturing June 15, 2026 (effective interest rate of 3.3%) 745 744 Series U Notes, interest rate of 3.1%, face amount of $291, maturing February 15, 2023 (effective interest rate of 3.1%) 291 291 Series V Notes, interest rate of 3.8%, face amount of $318, maturing March 15, 2025 (effective interest rate of 2.8%) 330 332 Series W Notes, interest rate of 4.5%, face amount of $278, maturing October 1, 2034 (effective interest rate of 4.1%) 290 291 Series X Notes, interest rate of 4.0%, face amount of $450, maturing April 15, 2028 (effective interest rate of 4.2%) 445 444 Series Y Notes, floating rate, face amount of $550, matured December 1, 2020 — 549 Series Z Notes, interest rate of 4.2%, face amount of $350, maturing December 1, 2023 (effective interest rate of 4.4%) 348 347 Series AA Notes, interest rate of 4.7%, face amount of $300, maturing December 1, 2028 (effective interest rate of 4.8%) 297 297 Series BB Notes, floating rate, face amount of $300, maturing March 8, 2021 (effective interest rate of 0.9% at December 31, 2020) 300 299 Series CC Notes, interest rate of 3.6%, face amount of $550, maturing April 15, 2024 (effective interest rate of 3.9%) 586 564 Series DD Notes, interest rate of 2.1%, face amount of $224, maturing October 3, 2022 (effective interest rate of 1.2%) 228 543 Series EE Notes, interest rate of 5.8%, face amount of $1,600, maturing May 1, 2025 (effective interest rate of 6.0%) 1,583 — Series FF Notes, interest rate of 4.6%, face amount of $1,000, maturing June 15, 2030 (effective interest rate of 4.8%) 986 — Series GG Notes, interest rate of 3.5%, face amount of $1,000, maturing October 15, 2032 (effective interest rate of 3.7%) 985 — Commercial paper — 3,197 Credit Facility 900 — Finance lease obligations 153 157 Other 143 247 $ 10,376 $ 10,940 Less current portion (1,173) (977) $ 9,203 $ 9,963 All our long-term debt is recourse to us but unsecured, other than debt assumed in our acquisition of Elegant which we paid off in January 2020 and debt associated with one of our owned properties. All the Senior Notes shown in the table above are our unsecured and unsubordinated obligations, which rank equally with our other Senior Notes and all other unsecured and unsubordinated indebtedness that we have issued or will issue from time to time, and are governed by the terms of an indenture, dated as of November 16, 1998, between us and The Bank of New York Mellon (formerly The Bank of New York), as trustee. With the exception of the floating rate Series BB Notes, we may redeem some or all of each series of the Senior Notes before maturity under the terms provided in the applicable form of Senior Note. We are party to a multicurrency revolving credit agreement (as amended, the “Credit Facility”) that provides for up to $4.5 billion of aggregate effective borrowings for general corporate needs, including working capital, capital expenditures, letters of credit, acquisitions and to support our commercial paper program if and when we resume issuing commercial paper. Borrowings under the Credit Facility generally bear interest at LIBOR (the London Interbank Offered Rate) plus a spread based on our public debt rating. We also pay quarterly fees on the Credit Facility at a rate based on our public debt rating. We classify outstanding borrowings under the Credit Facility and outstanding commercial paper borrowings (if any) as long-term based on our ability and intent to refinance the outstanding borrowings on a long-term basis. The Credit Facility expires on June 28, 2024. In 2020, we made borrowings of $4.5 billion and repayments of $3.6 billion, resulting in total outstanding borrowings under the Credit Facility of $0.9 billion as of December 31, 2020. In April 2020, we entered into an amendment to the Credit Facility (the “First Credit Facility Amendment”). The First Credit Facility Amendment waives the quarterly-tested leverage covenant in the Credit Facility through and including the first quarter of 2021 (the “Covenant Waiver Period”), which waiver period may end sooner at our election, adjusts the required leverage levels for the covenant when it is re-imposed at the end of the Covenant Waiver Period, and imposes a new monthly-tested liquidity covenant for the duration of the Covenant Waiver Period. The First Credit Facility Amendment also makes certain other amendments to the terms of the Credit Facility, including increasing the interest and fees payable on the Credit Facility for the duration of the Covenant Waiver Period, tightening certain existing covenants, and imposing additional covenants for the duration of the Covenant Waiver Period. These covenant changes include tightening the lien covenant and the covenant on dividends, share repurchases and distributions, and imposing new covenants limiting asset sales, investments and discretionary capital expenditures. In January 2021, we entered into two more amendments to the Credit Facility (the “New Credit Facility Amendments,” and together with the First Credit Facility Amendment, the “Credit Facility Amendments”), which extend the Covenant Waiver Period through and including the fourth quarter of 2021 (which waiver period may end sooner at our election), revise the required leverage levels for such covenant when it is re-imposed at the end of the Covenant Waiver Period (starting at 5.50 to 1.00 when the leverage test is first re-imposed and gradually stepping down to 4.00 to 1.00 over the succeeding five fiscal quarters, as further described in the Credit Facility), and increase the minimum liquidity amount under the liquidity covenant that is tested monthly for the duration of the Covenant Waiver Period. The New Credit Facility Amendments also make certain other amendments to the terms of the Credit Facility, including reducing the rate floor for the LIBOR Daily Floating Rate and the Eurocurrency Rate. In April 2020, we issued $1.6 billion aggregate principal amount of 5.750 percent Series EE Notes due May 1, 2025 (the “Series EE Notes”). We pay interest on the Series EE Notes in May and November of each year, commencing in November 2020. We received net proceeds of approximately $1.581 billion from the offering of the Series EE Notes, after deducting the underwriting discount and estimated expenses, which were made available for general corporate purposes. In June 2020, we issued $1.0 billion aggregate principal amount of 4.625 percent Series FF Notes due June 15, 2030 (the “Series FF Notes”). We pay interest on the Series FF Notes in June and December of each year, commencing in December 2020. We received net proceeds of approximately $985 million from the offering of the Series FF Notes, after deducting the underwriting discount and estimated expenses. We used the majority of these proceeds to repurchase Senior Notes with near term maturities, as further described below. In June 2020, we completed a tender offer (the “Tender Offer”) and retired $853 million aggregate principal amount of our Senior Notes consisting of: • $351 million of our 2.3% Series Q Notes maturing January 15, 2022; • $176 million of our 3.3% Series L Notes maturing September 15, 2022; and • $326 million of our 2.1% Series DD Notes maturing October 3, 2022. We used proceeds from our Series FF Notes offering to complete the repurchase of such notes, including the payment of accrued interest and other costs incurred. In July 2020, we redeemed all $350 million aggregate principal amount of our Series M Notes due in October 2020. In August 2020, we issued $1.0 billion aggregate principal amount of 3.500 percent Series GG Notes due October 15, 2032 (the “Series GG Notes”). We will pay interest on the Series GG Notes in April and October of each year, commencing in April 2021. We received net proceeds of approximately $984 million from the offering of the Series GG Notes, after deducting the underwriting discount and estimated expenses, which were made available for general corporate purposes, including the repayment of a portion of our outstanding borrowings under the Credit Facility. The following table presents future principal payments, net of discounts, premiums, and debt issuance costs, for our debt at year-end 2020: Debt Principal Payments ($ in millions) Amount 2021 $ 1,173 2022 807 2023 682 2024 1,494 2025 2,302 Thereafter 3,918 Balance at year-end 2020 $ 10,376

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS AND GOODWILL	INTANGIBLE ASSETS AND GOODWILL The following table details the composition of our intangible assets at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Definite-lived Intangible Assets Costs incurred to obtain contracts with customers $ 1,674 $ 1,588 Contracts acquired in business combinations and other 2,257 1,972 3,931 3,560 Accumulated amortization (937) (808) 2,994 2,752 Indefinite-lived Intangible Brand Assets 5,995 5,889 $ 8,989 $ 8,641 We capitalize direct costs that we incur to obtain management, franchise, and license agreements. We amortize these costs on a straight-line basis over the initial term of the agreements, ranging from 15 to 30 years. In 2020, we recorded impairment charges totaling $64 million in the “Contract investment amortization” caption of our Income Statements to reduce the carrying amount of certain capitalized costs incurred to obtain contracts with customers, primarily due to the impact of COVID-19, most of which we recorded in our U.S. & Canada business segment. For acquired definite-lived intangible assets, we recorded amortization expense of $97 million in 2020, $105 million in 2019, and $111 million in 2018 in the “Depreciation, amortization, and other” caption of our Income Statements. For these assets, we estimate that our aggregate amortization expense will be $95 million for each of the next five fiscal years. The following table details the carrying amount of our goodwill at year-end 2020 and 2019: ($ in millions) U.S. & Canada Asia Pacific EMEA CALA Total Balance at year-end 2019 $ 5,338 $ 1,864 $ 1,522 $ 324 $ 9,048 Foreign currency translation 9 71 57 (10) 127 Balance at year-end 2020 $ 5,347 $ 1,935 $ 1,579 $ 314 $ 9,175

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT The following table presents the composition of our property and equipment balances at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Land $ 688 $ 684 Buildings and leasehold improvements 1,045 1,100 Furniture and equipment 640 1,225 Construction in progress 29 196 2,402 3,205 Accumulated depreciation (888) (1,301) $ 1,514 $ 1,904 We record property and equipment at cost, including interest and real estate taxes we incur during development and construction. We capitalize the cost of improvements that extend the useful life of property and equipment when we incur them. These capitalized costs may include structural costs, equipment, fixtures, floor, and wall coverings. We expense all repair and maintenance costs when we incur them. We compute depreciation using the straight-line method over the estimated useful lives of the assets (generally three

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS We believe that the fair values of our current assets and current liabilities approximate their reported carrying amounts. We present the carrying values and the fair values of noncurrent financial assets and liabilities that qualify as financial instruments, determined under current guidance for disclosures on the fair value of financial instruments, in the following table: At Year-End 2020 At Year-End 2019 ($ in millions) Carrying Fair Value Carrying Fair Value Senior, mezzanine, and other loans $ 159 $ 142 $ 117 $ 112 Total noncurrent financial assets $ 159 $ 142 $ 117 $ 112 Senior Notes $ (8,031) $ (8,941) $ (6,441) $ (6,712) Commercial paper/Credit Facility (900) (900) (3,197) (3,197) Other long-term debt (126) (128) (174) (179) Other noncurrent liabilities (426) (426) (196) (196) Total noncurrent financial liabilities $ (9,483) $ (10,395) $ (10,008) $ (10,284) We estimate the fair value of our senior, mezzanine, and other loans by discounting cash flows using risk-adjusted rates, both of which are Level 3 inputs. We estimate the fair value of our other long-term debt, excluding leases, using expected future payments discounted at risk-adjusted rates, which are Level 3 inputs. We determine the fair value of our Senior Notes using quoted market prices, which are directly observable Level 1 inputs. As discussed in Note 10, even though our commercial paper borrowings generally have short-term maturities of 30 days or less, we classify outstanding commercial paper borrowings (if any) as long-term based on our ability and intent to refinance them on a long-term basis. As we have historically been a frequent issuer of commercial paper, we use pricing from recent transactions as Level 2 inputs in estimating fair value. At year-end 2019, we determined that the carrying value of our commercial paper approximated fair value due to the short maturity. At year-end 2020, all of our previously issued commercial paper has matured and been repaid. Due to changes to our credit ratings as a result of the impact of COVID-19 on our business, we currently are not issuing commercial paper. The carrying value of our Credit Facility borrowings approximate fair value because they bear interest at a market rate. Our other noncurrent liabilities largely consist of guarantees. As we note in the “Guarantees” caption of Note 2, we measure our liability for guarantees at fair value on a nonrecurring basis, which is when we issue or modify a guarantee using Level 3 internally developed inputs. At year-end 2020 and year-end 2019, we determined that the carrying values of our guarantee liabilities approximated their fair values based on Level 3 inputs. See the “Fair Value Measurements” caption of Note 2 for more information on the input levels we use in determining fair value.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table details the accumulated other comprehensive loss activity for 2020, 2019, and 2018: ($ in millions) Foreign Currency Translation Adjustments Derivative Instrument and Other Adjustments Accumulated Other Comprehensive Loss Balance at year-end 2017 $ (23) $ 6 $ (17) Other comprehensive (loss) income before reclassifications (1) (391) 4 (387) Reclassification adjustments 11 6 17 Net other comprehensive (loss) income (380) 10 (370) Adoption of ASU 2016-01 — (4) (4) Balance at year-end 2018 $ (403) $ 12 $ (391) Other comprehensive income before reclassifications (1) 35 2 37 Reclassification adjustments — (7) (7) Net other comprehensive income (loss) 35 (5) 30 Balance at year-end 2019 $ (368) $ 7 $ (361) Other comprehensive income before reclassifications (1) 229 7 236 Reclassification adjustments — (10) (10) Net other comprehensive income (loss) 229 (3) 226 Balance at year-end 2020 $ (139) $ 4 $ (135) (1) Other comprehensive (loss) income before reclassifications for foreign currency translation adjustments includes intra-entity foreign currency transactions that are of a long-term investment nature, which resulted in (losses) gains of $(44) million for 2020, $6 million for 2019, and $14 million for 2018.

BUSINESS SEGMENTS

BUSINESS SEGMENTS	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
BUSINESS SEGMENTS	BUSINESS SEGMENTS We discuss our operations in the following three reportable business segments: United States and Canada (“U.S. & Canada”); Asia Pacific; and Europe, Middle East and Africa (“EMEA”). Our Caribbean and Latin America (“CALA”) operating segment does not meet the applicable accounting criteria for separate disclosure as a reportable business segment, and we include its results in “Unallocated corporate and other.” In the 2020 fourth quarter, we changed the name of our largest segment from “North America” to “U.S. & Canada.” Other than the name change, we made no other changes to the composition of this segment. In January 2021, we modified our reportable segment structure as a result of a change in the way management intends to evaluate results and allocate resources within the Company. Beginning with the 2021 first quarter, we will report the following two operating segments: U.S. & Canada and International. We evaluate the performance of our operating segments using “segment profits/loss” which is based largely on the results of the segment without allocating corporate expenses, income taxes, indirect general, administrative, and other expenses, merger-related costs, or above-property restructuring charges. We assign gains and losses, equity in earnings or losses, direct general, administrative, and other expenses, and other restructuring charges to each of our segments. “Unallocated corporate and other” includes a portion of our revenues, including license fees we receive from our credit card programs, fees from vacation ownership licensing agreements, revenues and expenses for our Loyalty Program, general, administrative, and other expenses, restructuring and merger-related charges, equity in earnings or losses, and other gains or losses that we do not allocate to our segments as well as results of our CALA operating segment. Our chief operating decision maker monitors assets for the consolidated Company, but does not use assets by operating segment when assessing performance or making operating segment resource allocations. Segment Revenues The following tables present our revenues disaggregated by segment and major revenue stream for the last three fiscal years: 2020 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 914 $ 183 $ 110 $ 1,207 Contract investment amortization (108) (7) (12) (127) Net fee revenues 806 176 98 1,080 Owned, leased, and other revenue 198 89 153 440 Cost reimbursement revenue 6,901 347 507 7,755 Total reportable segment revenue $ 7,905 $ 612 $ 758 $ 9,275 Unallocated corporate and other 1,296 Total revenue $ 10,571 2019 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 2,265 $ 477 $ 418 $ 3,160 Contract investment amortization (48) (2) (8) (58) Net fee revenues 2,217 475 410 3,102 Owned, leased, and other revenue 715 178 553 1,446 Cost reimbursement revenue 13,901 536 969 15,406 Total reportable segment revenue $ 16,833 $ 1,189 $ 1,932 $ 19,954 Unallocated corporate and other 1,018 Total revenue $ 20,972 2018 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 2,158 $ 479 $ 387 $ 3,024 Contract investment amortization (45) (2) (7) (54) Net fee revenues 2,113 477 380 2,970 Owned, leased, and other revenue 721 182 563 1,466 Cost reimbursement revenue 13,455 459 926 14,840 Total reportable segment revenue $ 16,289 $ 1,118 $ 1,869 $ 19,276 Unallocated corporate and other 1,482 Total revenue $ 20,758 Revenues attributed to operations located outside the U.S. were $1,910 million in 2020, $4,400 million in 2019, and $4,246 million in 2018, including cost reimbursement revenue outside the U.S. of $1,247 million in 2020, $2,394 million in 2019, and $2,244 million in 2018. Segment Profits and Losses ($ in millions) 2020 2019 2018 U.S. & Canada (1) $ 198 $ 2,000 $ 1,939 Asia Pacific (2) 1 369 456 EMEA (3) (200) 318 328 Unallocated corporate and other (47) (720) (60) Interest expense, net of interest income (418) (368) (318) Benefit (provision) for income taxes 199 (326) (438) Net (loss) income $ (267) $ 1,273 $ 1,907 (1) Includes cost reimbursements, net of $(80) million in 2020, $(129) million in 2019, and $(121) million in 2018. (2) Includes cost reimbursements, net of $(18) million in 2020, $(9) million in 2019, and zero in 2018. (3) Includes cost reimbursements, net of $(33) million in 2020, $(8) million in 2019, and zero in 2018. Segment (losses) profits attributed to operations located outside the U.S. were $(198) million in 2020, $982 million in 2019, and $1,155 million in 2018, including cost reimbursements, net (cost reimbursement revenue, net of reimbursed expenses) outside the U.S. of $(62) million in 2020, $(18) million in 2019, and $(14) million in 2018. Depreciation, Amortization, and Other ($ in millions) 2020 2019 2018 U.S. & Canada $ 209 $ 218 $ 97 Asia Pacific 30 25 26 EMEA 58 51 51 Unallocated corporate and other 49 47 52 $ 346 $ 341 $ 226 Capital Expenditures ($ in millions) 2020 2019 2018 U.S. & Canada $ 12 $ 287 $ 305 Asia Pacific 2 2 6 EMEA 12 29 36 Unallocated corporate and other 109 335 209 $ 135 $ 653 $ 556

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Equity Method Investments We have equity method investments in entities that own properties for which we provide management services and receive fees. In addition, in some cases we provide loans, preferred equity, or guarantees to these entities. The following table presents Income Statement data resulting from transactions with these related parties. This table does not include our Financial Statement captions with insignificant related party activity. ($ in millions) 2020 2019 2018 Cost reimbursement revenue $ 107 $ 233 $ 332 Reimbursed expenses (110) (236) (337) Equity in (losses) earnings (141) 13 103 Summarized Financial Information for Investees The following tables present summarized financial information for the entities in which we have equity method investments: ($ in millions) 2020 2019 2018 Sales $ 259 $ 815 $ 932 Net (loss) income (212) 80 221 ($ in millions) At Year-End 2020 At Year-End 2019 Assets (primarily composed of hotel real estate managed by us) $ 2,348 $ 2,555 Liabilities 1,623 1,691 The carrying amount of our equity method investments was $422 million at year-end 2020 and $577 million at year-end 2019. This value exceeded our share of the book value of the investees’ net assets by $294 million at year-end 2020 and $311 million at year-end 2019, primarily due to the value that we assigned to land, contracts, and buildings owned by the investees. In 2020, we recorded impairment charges totaling $77 million in the “Equity in (losses) earnings” caption of our Income Statements to reduce the carrying amount of certain investments, primarily due to the impact of COVID-19, most of which we recorded in our U.S. & Canada business segment. Other Related Parties We received management fees of approximately $3 million in 2020, $12 million in 2019, and $13 million in 2018, plus reimbursement of certain expenses, from our operation of properties owned by JWM Family Enterprises, L.P., which is beneficially owned and controlled by J.W. Marriott, Jr., Deborah Marriott Harrison, and other members of the Marriott family.

RELATIONSHIP WITH MAJOR CUSTOME

RELATIONSHIP WITH MAJOR CUSTOMER	12 Months Ended
	Dec. 31, 2020
Relationship with Major Customer Disclosure [Abstract]
RELATIONSHIP WITH MAJOR CUSTOMER	RELATIONSHIP WITH MAJOR CUSTOMER Host Hotels & Resorts, Inc., formerly known as Host Marriott Corporation, and its affiliates (“Host”) owned or leased 59 lodging properties at year-end 2020 and 60 at year-end 2019 that we operated or franchised. Over the last three years, we recognized revenues, including cost reimbursement revenue, of $1,037 million in 2020, $2,406 million in 2019, and $2,542 million in 2018 from those lodging properties, and included those revenues in our U.S. & Canada and Europe, Middle East and Africa reportable business segments, and our Caribbean and Latin America operating segment.

SUPPLEMENTARY DATA QUARTERLY FI

SUPPLEMENTARY DATA QUARTERLY FINANCIAL DATA - UNAUDITED	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
SUPPLEMENTARY DATA QUARTERLY FINANCIAL DATA - UNAUDITED	SUPPLEMENTARY DATA QUARTERLY FINANCIAL DATA – UNAUDITED ($ in millions, except per share data) 2020 First Second Third Fourth Fiscal Revenues $ 4,681 $ 1,464 $ 2,254 $ 2,172 $ 10,571 Operating income (loss) $ 114 $ (154) $ 252 $ (128) $ 84 Net income (loss) $ 31 $ (234) $ 100 $ (164) $ (267) Basic earnings (loss) per share (1) $ 0.10 $ (0.72) $ 0.31 $ (0.50) $ (0.82) Diluted earnings (loss) per share (1) $ 0.09 $ (0.72) $ 0.31 $ (0.50) $ (0.82) ($ in millions, except per share data) 2019 First Second Third Fourth Fiscal Revenues $ 5,012 $ 5,305 $ 5,284 $ 5,371 $ 20,972 Operating income $ 510 $ 409 $ 607 $ 274 $ 1,800 Net income $ 375 $ 232 $ 387 $ 279 $ 1,273 Basic earnings per share (1) $ 1.10 $ 0.70 $ 1.17 $ 0.85 $ 3.83 Diluted earnings per share (1) $ 1.09 $ 0.69 $ 1.16 $ 0.85 $ 3.80 (1) The sum of the earnings per share for the four quarters may differ from annual earnings per share due to the required method of computing the weighted average shares in interim periods.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	In order to make this report easier to read, we also refer throughout to (1) our Consolidated Financial Statements as our “Financial Statements,” (2) our Consolidated Statements of (Loss) Income as our “Income Statements,” (3) our Consolidated Balance Sheets as our “Balance Sheets,” (4) our Consolidated Statements of Cash Flows as our “Statements of Cash Flows,” (5) our properties, brands, or markets in the United States and Canada as “U.S. & Canada,” and (6) our properties, brands, or markets in our Caribbean and Latin America region, Europe, Middle East and Africa segment, and Asia Pacific segment as “International.” In addition, references throughout to numbered “Notes” refer to these Notes to Consolidated Financial Statements, unless otherwise stated.Preparation of financial statements that conform with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the financial statements, the reported amounts of revenues and expenses during the reporting periods, and the disclosures of contingent liabilities. The uncertainty created by the coronavirus and efforts to contain it (“COVID-19”) has made such estimates more difficult and subjective. Accordingly, ultimate results could differ from those estimates.The accompanying Financial Statements reflect all normal and recurring adjustments necessary to present fairly our financial position at fiscal year-end 2020 and fiscal year-end 2019 and the results of our operations and cash flows for fiscal years 2020, 2019, and 2018. We have eliminated all material intercompany transactions and balances between entities consolidated in these Financial Statements.
Revenue	Base Management and Incentive Management Fees : For our managed hotels, we have performance obligations to provide hotel management services and a license to our intellectual property for the use of our brand names. As compensation for such services, we are generally entitled to receive base fees, which are a percentage of the revenues of hotels, and incentives fees, which are generally based on a measure of hotel profitability. Both the base and incentive management fees are variable consideration, as the transaction price is based on a percentage of revenue or profit, as defined in each contract. We recognize base management fees on a monthly basis over the term of the agreement as those amounts become payable. We recognize incentive management fees on a monthly basis over the term of the agreement based on each property’s financial results, as long as we do not expect a significant reversal due to projected future hotel performance or cash flows in future periods. Franchise Fee and Royalty Fee Revenue : For our franchised hotels, we have a performance obligation to provide franchisees and operators a license to our intellectual property for use of certain of our brand names. As compensation for such services, we are typically entitled to initial application fees and ongoing royalty fees. Our ongoing royalty fees represent variable consideration, as the transaction price is based on a percentage of certain revenues of the hotels, as defined in each contract. We recognize royalty fees on a monthly basis over the term of the agreement as those amounts become payable. Initial application and relicensing fees are fixed consideration payable upon submission of a franchise application or renewal and are recognized on a straight-line basis over the initial or renewal term of the franchise agreements. Owned and Leased Hotel Revenue : At our owned and leased hotels, we have performance obligations to provide accommodations and other ancillary services to hotel guests. As compensation for such goods and services, we are typically entitled to a fixed nightly fee for an agreed upon period and additional fixed fees for any ancillary services purchased. These fees are generally payable at the time the hotel guest checks out of the hotel. We generally satisfy the performance obligations over time, and we recognize the revenue from room sales and from other ancillary guest services on a daily basis, as the rooms are occupied and we have rendered the services. Cost Reimbursements : Under our management and franchise agreements, we are entitled to be reimbursed for certain costs we incur on behalf of the managed, franchised, and licensed properties, with no added mark-up. These costs primarily consist of payroll and related expenses at managed properties where we are the employer of the employees at the properties and include certain operational and administrative costs as provided for in our contracts with the owners. We are entitled to reimbursement in the period we incur the related reimbursable costs, which we recognize within the “Cost reimbursement revenue” caption of our Income Statements. Under our management and franchise agreements, hotel owners and franchisees participate in certain centralized programs and services, such as marketing, sales, reservations, and insurance programs. We operate these programs and services for the benefit of our hotel owners. We do not operate these programs and services to generate a profit over the long term, and accordingly, when we recover the costs that we incur for these programs and services from our hotel owners, we do not seek a mark-up. The amounts we charge for these programs and services are generally a combination of fixed fees and variable fees based on sales or other metrics and are payable on a monthly basis. We generally recognize revenue within the “Cost reimbursement revenue” caption of our Income Statements when the amounts may be billed to hotel owners, and we recognize expenses within the “Reimbursed expenses” caption as they are incurred. This pattern of recognition results in timing differences between the costs incurred for centralized programs and services and the related reimbursement from hotel owners in our operating and net income. Over the long term, these programs and services are not designed to impact our economics, either positively or negatively. In addition, we present in the “Reimbursed expenses” caption of our Income Statements spending funded by the proceeds ($664 million, $425 million after-tax) from the 2017 sale of our interest in Avendra LLC, which we committed would be used for the benefit of hotels in our system. Such spending totaled $62 million ($46 million after-tax) in 2020, $118 million ($87 million after-tax) in 2019, and $115 million ($85 million after-tax) in 2018. Other Revenue : Includes Global Design fees, which we describe below, termination fees, and other property and brand revenues. We generally recognize termination fees when collection is probable and other revenue as services are rendered. Amounts received in advance are deferred as liabilities. We provide hotel design and construction review quality assurance (“Global Design”) services to our managed and franchised hotel owners, generally during the period prior to a hotel’s opening or during the period a hotel is converting to a Marriott brand (the “pre-opening period”). As compensation for such services, we may be entitled to receive a one-time fixed fee that is payable during the pre-opening period of the hotel. As these services are not a distinct performance obligation, we recognize the fees on a straight-line basis over the initial term of the management or franchise agreement within the “Owned, leased, and other revenue” caption of our Income Statements. Practical Expedients and Exemptions : We do not disclose the amount of variable consideration that we expect to recognize in future periods in the following circumstances: (1) if we recognize the revenue based on the amount invoiced or services performed; (2) for sales-based or usage-based royalty promised in exchange for a license of intellectual property; or (3) if the consideration is allocated entirely to a wholly unsatisfied promise to transfer a distinct service that forms part of a single performance obligation, and the terms of the consideration relate specifically to our efforts to transfer, or to a specific outcome from transferring the service. We are required to collect certain taxes and fees from customers on behalf of governmental agencies and remit these to the applicable governmental agencies on a periodic basis. We do not include these taxes in determining the transaction price. revenue” caption on our Income Statements, as our performance obligation is to facilitate the transaction between the Loyalty Program member and the managed or franchised property or program partner. Our redemption cost, which is generally based on redemption rates that can increase in periods in which occupancy at the property exceeds a certain threshold, could be higher or lower than our revenue recognized in any given period. We recognize all other Loyalty Program costs as incurred in our “Reimbursed expenses” caption. We have multi-year agreements for our co-brand credit cards associated with our Loyalty Program. Under these agreements, we have performance obligations to provide a license to the intellectual property associated with our brands and marketing lists (“Licensed IP”) to the financial institutions that issue the credit cards, to arrange for the redemption of Loyalty Program points as discussed in the preceding paragraph, and to arrange for the redemption of free night certificates provided to cardholders. We receive fees from these agreements, including fixed amounts that are primarily payable at contract inception, and variable amounts that are paid to us monthly over the term of the agreements, based on: (1) the number of free night certificates issued and redeemed; (2) the number of Loyalty Program points purchased; and (3) the volume of cardholder spend. We allocate those fees among the performance obligations, including the Licensed IP, our Loyalty Program points, and free night certificates provided to cardholders based on their estimated standalone selling prices. The estimation of the standalone selling prices requires significant judgments based upon generally accepted valuation methodologies regarding the value of our Licensed IP, the amount of funding we will receive, and the number of Loyalty Program points and free night certificates we will issue over the term of the agreements. We base our estimates of these amounts on our historical experience and expectation of future cardholder behavior. We recognize the portion of the Licensed IP revenue that meets the sales-based royalty criteria as the credit cards are used and the remaining portion of the Licensed IP revenue on a straight-line basis over the contract term. In our Income Statements, we primarily recognize Licensed IP revenue in the “Franchise fees” caption, and we recognize a portion in the “Cost reimbursement revenue” caption. We recognize the revenue related to the Loyalty Program points as discussed in the preceding paragraph. We recognize the revenue related to the free night certificates when the related service is provided. We recognize revenue net of the redemption cost, as our performance obligation is to facilitate the transaction between the Loyalty Program member and the managed or franchised property. Contract Balances : We generally receive payments from customers as we satisfy our performance obligations. We record a receivable when we have an unconditional right to receive payment and only the passage of time is required before payment is due. We record deferred revenue when we receive payment, or have the unconditional right to receive payment, in advance of the satisfaction of our performance obligations related to franchise application and relicensing fees, Global Design fees, credit card branding license fees, and our Loyalty Program. Current and noncurrent deferred revenue increased by $907 million, to $1,867 million at December 31, 2020 from $960 million at December 31, 2019, primarily as a result of amendments to the existing agreements for our U.S.-issued co-brand credit cards associated with our Loyalty Program, which we signed in May 2020. These amendments provided the Company with $920 million of cash from the prepayment of certain future revenues, the early payment of a previously committed signing bonus, and the pre-purchase of Marriott Bonvoy points and other consideration. We recorded the amount of cash received primarily in the deferred revenue caption, and the remainder in the liability for guest loyalty program captions, on our Balance Sheet. Our current and noncurrent Loyalty Program liability increased by $553 million, to $6,271 million at December 31, 2020, from $5,718 million at December 31, 2019, primarily reflecting an increase in points earned by members, partially offset by $1,118 million of revenue recognized in 2020, that was deferred as of December 31, 2019. The current portion of our Loyalty Program liability decreased compared to December 31, 2019, due to lower estimated redemptions in the short-term as a result of COVID-19. At each reporting period, we evaluate the estimates used in the recognition of Loyalty Program revenues, including estimates of the breakage of points that members will never redeem and the amount of funding we expect to receive over the life of the agreements with various third parties. In 2020, the updated estimates resulted in a net decrease in deferred revenue, and a corresponding ne t increase in rev enue of approximately $47 million.
Real Estate Sales	We recognize a gain or loss on real estate transactions when control of the asset transfers to the buyer, generally at the time the sale closes. In sales transactions where we retain a management contract, the terms and conditions of the management contract are generally comparable to the terms and conditions of the management contracts obtained directly with third-party owners in competitive processes.
Retirement Savings Plan	We contribute to tax-qualified retirement plans for the benefit of U.S. employees who meet certain eligibility requirements and choose to participate in the plans. Participating employees specify the percentage or amount of salary they wish to contribute from their compensation, and the Company typically makes discretionary and certain other matching or supplemental contributions.
Non-U.S. Operations	The U.S. dollar is the functional currency of our consolidated and unconsolidated entities operating in the U.S. The functional currency of our consolidated and unconsolidated entities operating outside of the U.S. is generally the principal currency of the economic environment in which the entity primarily generates and expends cash. We translate the financial statements of consolidated entities whose functional currency is not the U.S. dollar into U.S. dollars, and we do the same, as needed, for unconsolidated entities whose functional currency is not the U.S. dollar. We translate assets and liabilities at the exchange rate in effect as of the financial statement date and translate income statement accounts using the weighted average exchange rate for the period. We include translation adjustments from currency exchange and the effect of exchange rate changes on intercompany transactions of a long-term investment nature as a separate component of stockholders’ equity. We report gains and losses from currency exchange rate changes for intercompany receivables and payables that are not of a long-term investment nature, as well as for third-party transactions, currently in operating costs and expenses.
Stock-Based Compensation	Our stock-based compensation awards primarily consist of restricted stock units (“RSUs”). We measure compensation costs for our stock-based payment transactions at fair value based on the closing stock price on the grant date, and we recognize those costs in our Financial Statements over the vesting period during which the employee provides service in exchange for the award.
Advertising Costs	We expense costs to produce advertising as they are incurred and to communicate advertising as the communication occurs and record such amounts in reimbursed expenses to the extent undertaken on behalf of our owners and franchisees.
Income Taxes	We record the amounts of taxes payable or refundable for the current year, as well as deferred tax liabilities and assets for the future tax consequences of events we have recognized in our Financial Statements or tax returns, using judgment in assessing future profitability and the likely future tax consequences of those events. We base our estimates of deferred tax assets and liabilities on current tax laws, rates and interpretations, and, in certain cases, business plans and other expectations about future outcomes. We develop our estimates of future profitability based on our historical data and experience, industry projections, micro and macro general economic condition projections, and our expectations. We account for U.S. tax on Global Intangible Low-Taxed Income in the period incurred. We generally recognize the effect of the tax law changes in the period of enactment. Changes in existing tax laws and rates, their related interpretations, and the uncertainty generated by the current economic environment may affect the amounts of our deferred tax liabilities or the valuations of our deferred tax assets over time. Our accounting for deferred tax consequences represents management’s best estimate of future events that can be appropriately reflected in the accounting estimates.
Cash and Equivalents	We consider all highly liquid investments with an initial maturity of three months or less at date of purchase to be cash equivalents.
Accounts Receivable	Our accounts receivable primarily consist of amounts due from hotel owners with whom we have management and franchise agreements and include reimbursements of costs we incurred on behalf of managed and franchised properties. We record an allowance for credit losses measured over the contractual life of the instrument based on an assessment of historical collection activity and current and forecasted future economic conditions by region.
Assets Held for Sale	We consider properties to be assets held for sale when (1) management commits to a plan to sell the property; (2) it is unlikely that the disposal plan will be significantly modified or discontinued; (3) the property is available for immediate sale in its present condition; (4) actions required to complete the sale of the property have been initiated; (5) sale of the property is probable and we expect the completed sale will occur within one year; and (6) the property is actively being marketed for sale at a price that is reasonable given our estimate of current market value. Upon designation of a property as an asset held for sale, we record the property’s value at the lower of its carrying value or its estimated fair value, less estimated costs to sell, and we cease depreciation.
Goodwill	We test goodwill for potential impairment at least annually in the fourth quarter, or more frequently if an event or other circumstance indicates that we may not be able to recover the carrying amount of the net assets of the reporting unit. In evaluating goodwill for impairment, we may assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If we bypass the qualitative assessment, or if we conclude that it is more likely than not that the fair value of a reporting unit is less than its carrying value, then we perform a quantitative impairment test by comparing the fair value of a reporting unit with its carrying amount. We calculate the estimated fair value of a reporting unit using a combination of the income and market approaches. For the income approach, we use internally developed discounted cash flow models that include the following assumptions, among others: projections of revenues, expenses, and related cash flows based on assumed long-term growth rates and demand trends; expected future investments to grow new units; and estimated discount rates. For the market approach, we use internal analyses based primarily on market comparables. We base these assumptions on our historical data and experience, third-party appraisals, industry projections, micro and macro general economic condition projections, and our expectations.
Intangibles and Long-Lived Assets	We assess indefinite-lived intangible assets for continued indefinite use and for potential impairment annually, or more frequently if an event or other circumstance indicates that we may not be able to recover the carrying amount of the asset. Like goodwill, we may first assess qualitative factors to determine whether it is more likely than not that the fair value of the indefinite-lived intangible is less than its carrying amount. If the carrying value of the asset exceeds the fair value, we recognize an impairment loss in the amount of that excess. We test definite-lived intangibles and long-lived asset groups for recoverability when changes in circumstances indicate that we may not be able to recover the carrying value; for example, when there are material adverse changes in projected revenues or expenses, significant underperformance relative to historical or projected operating results, or significant negative industry or economic trends. We also test recoverability when management has committed to a plan to sell or otherwise dispose of an asset group and we expect to complete the plan within a year. We evaluate recoverability of an asset group by comparing its carrying value, including right-of-use assets, to the future net undiscounted cash flows that we expect the asset group will generate. If the comparison indicates that we will not be able to recover the carrying value of an asset group, we recognize an impairment loss for the amount by which the carrying value exceeds the estimated fair value. When we recognize an impairment loss for assets to be held and used, we depreciate the adjusted carrying amount of those assets over their remaining useful life. We calculate the estimated fair value of an intangible asset or asset group using the income approach or the market approach. We utilize the same assumptions and methodology for the income approach that we describe in the “ Goodwill
Investments	We hold equity interests in ventures established to develop or acquire and own hotel properties or that otherwise support our hospitality operations. We account for these investments as either an equity method investment, a financial asset, or a controlled subsidiary. We apply the equity method of accounting if we have significant influence over the entity, typically when we hold 20 percent or more of the voting common stock (or equivalent) of an investee but do not have a controlling financial interest. In certain circumstances, such as with investments in limited liability companies or limited partnerships, we apply the equity method of accounting when we own as little as three to five percent. We account for financial assets at fair value if it is readily determinable, or using the fair value alternative method, whereby investments are measured at cost less impairment, adjusted for observable price changes. We consolidate entities that we control. When we acquire an investment that qualifies for the equity method of accounting, we determine the acquisition date fair value of the identifiable assets and liabilities. If our carrying amount exceeds our proportional share in the equity of the investee, we amortize the difference on a straight-line basis over the underlying assets’ estimated useful lives when calculating equity method earnings attributable to us, excluding the difference attributable to land, which we do not amortize. We evaluate an investment for impairment when circumstances indicate that we may not be able to recover the carrying value. When evaluating our ventures, we consider loan defaults, significant underperformance relative to historical or projected operating performance, or significant negative industry or economic trends. Additionally, a venture’s commitment to a plan to sell some or all of its assets could cause us to evaluate the recoverability of the venture’s individual long-lived assets and possibly the venture itself. We impair investments we account for using the equity method of accounting when we determine that there has been an “other-than-temporary” decline in the venture’s estimated fair value compared to its carrying value. We perform qualitative assessments for investments we account for using the fair value alternative method and we record any associated impairment when the fair value is less than the carrying value. Under the accounting guidance for the consolidation of variable interest entities, we analyze our variable interests, including equity investments, loans, and guarantees, to determine if an entity in which we have a variable interest is a variable interest entity. Our analysis includes both quantitative and qualitative reviews. We base our quantitative analysis on the forecasted cash flows of the entity, and our qualitative analysis on our review of the design of the entity, its organizational structure including decision-making ability, and relevant financial agreements. We also use our qualitative analysis to determine if we must consolidate a variable interest entity as its primary beneficiary.
Fair Value Measurements	We have various financial instruments we must measure at fair value on a recurring basis, including certain marketable securities and derivatives. See Note 13 for further information. We also apply the provisions of fair value measurement to various nonrecurring measurements for our financial and nonfinancial assets and liabilities. Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). We measure our assets and liabilities using inputs from the following three levels of the fair value hierarchy: Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs). Level 3 includes unobservable inputs that reflect our assumptions about what factors market participants would use in pricing the asset or liability. We develop these inputs based on the best information available, including our own data.
Derivative Instruments	We record derivatives at fair value. The designation of a derivative instrument as a hedge and its ability to meet the hedge accounting criteria determine how we reflect the change in fair value of the derivative instrument in our Financial Statements. A derivative qualifies for hedge accounting if, at inception, we expect the derivative will be highly effective in offsetting the underlying hedged cash flows or fair value and we fulfill the hedge documentation standards at the time we enter into the derivative contract. We designate a hedge as a cash flow hedge, fair value hedge, or a hedge of the net investment in non-U.S. operations based on the exposure we are hedging. For the effective portion of qualifying cash flow hedges, we record changes in fair value in accumulated other comprehensive income (“AOCI”). We release the derivative’s gain or loss from AOCI to match the timing of the underlying hedged items’ effect on earnings. The change in fair value of qualifying fair value hedges as well as changes in fair value of the underlying hedged items to the hedged risks are recorded concurrently in earnings. We review the effectiveness of our hedging instruments quarterly and discontinue hedge accounting for any hedge that we no longer consider to be highly effective. We recognize changes in fair value for derivatives not designated as hedges or those not qualifying for hedge accounting in current period earnings. Upon termination of cash flow hedges, we release gains and losses from AOCI based on the timing of the underlying cash flows or revenue recognized, unless the termination results from the failure of the intended transaction to occur in the expected time frame. Such untimely transactions require us to immediately recognize in earnings the gains and/or losses that we previously recorded in AOCI. Changes in interest rates, currency exchange rates, and equity securities expose us to market risk. We manage our exposure to these risks by monitoring available financing alternatives, as well as through development and application of credit granting policies. We also use derivative instruments as part of our overall strategy to manage our exposure to market risks. As a matter of policy, we only enter into transactions that we believe will be highly effective at offsetting the underlying risk, and we do not use derivatives for trading or speculative purposes.
Loan Loss Reserves	We may make senior, mezzanine, and other loans to owners of hotels that we operate or franchise, generally to facilitate the development of a hotel and sometimes to facilitate brand programs or initiatives. We expect the owners to repay the loans in accordance with the loan agreements, or earlier as the hotels mature and capital markets permit. We use metrics such as loan-to-value ratios and debt service coverage, and other information about collateral and from third-party rating agencies to assess the credit quality of the loan receivable, both upon entering into the loan agreement and on an ongoing basis as applicable. At inception and throughout the term of the loan agreement, we individually assess loans for impairment. We consider current and forecasted future economic conditions in addition to our historical experience. We use internally generated cash flow projections to determine the likelihood that the loans will be repaid under the terms of the loan agreements. To measure impairment, we calculate the present value of expected future cash flows discounted at the loan’s original effective interest rate or the estimated fair value of the collateral. If the present value or the estimated collateral is less than the carrying value of the loan receivable, we establish a specific impairment reserve for the difference.
Leases	We determine if an arrangement is a lease or contains a lease at the inception of the contract. Our leases generally contain fixed and variable components. The variable components of our leases are primarily based on operating performance of the leased property. Our lease agreements may also include non-lease components, such as common area maintenance, which we combine with the lease component to account for both as a single lease component. Lease liabilities, which represent our obligation to make lease payments arising from the lease, and corresponding right-of-use assets, which represent our right to use an underlying asset for the lease term, are recognized at the commencement date of the lease based on the present value of fixed future payments over the lease term. We calculate the present value of future payments using the discount rate implicit in the lease, if available, or our incremental borrowing rate. For operating leases, lease expense relating to fixed payments is recognized on a straight-line basis over the lease term and lease expense relating to variable payments is expensed as incurred. For finance leases, the amortization of the asset is recognized over the shorter of the lease term or useful life of the underlying asset.
Guarantees	We measure and record our liability for the fair value of a guarantee on a nonrecurring basis, that is when we issue or modify a guarantee, using Level 3 internally developed inputs, as described above in this footnote under the caption “ Fair Value Measurements .” We base our calculation of the estimated fair value of a guarantee on the income approach or the market approach, depending on the type of guarantee. For the income approach, we use internally developed discounted cash flow and Monte Carlo simulation models that include the following assumptions, among others: projections of revenues and expenses and related cash flows based on assumed growth rates and demand trends; historical volatility of projected performance; the guaranteed obligations; and applicable discount rates. We base these assumptions on our historical data and experience, industry projections, micro and macro general economic condition projections, and our expectations. For the market approach, we use internal analyses based primarily on market comparable data and our assumptions about market capitalization rates, credit spreads, growth rates, and inflation. The offsetting entry for the guarantee liability depends on the circumstances in which the guarantee was issued. Funding under the guarantee reduces the recorded liability. In most cases, when we do not forecast any funding, we amortize the liability into income on a straight-line basis over the remaining term of the guarantee. On a quarterly basis, we evaluate all material estimated liabilities based on the operating results and the terms of the guarantee. If we conclude that it is probable that we will be required to fund a greater amount than previously estimated, we record a loss except to the extent that the applicable contracts provide that the advance can be recovered as a loan.
Self-Insurance Programs	We self-insure for certain levels of liability, workers’ compensation, property insurance and employee medical coverage. We accrue estimated costs of these self-insurance programs at the present value of projected settlements for known and incurred but not reported claims. We use a discount rate of two percent to determine the present value of the projected settlements, which we consider to be reasonable given our history of settled claims, including payment patterns and the fixed nature of the individual settlements. We classify the current portion of our self-insurance reserve in the “Accrued expenses and other” caption and the noncurrent portion in the “Other noncurrent liabilities” caption of our Balance Sheets.
Legal Contingencies	We are subject to various legal proceedings and claims, the outcomes of which are uncertain. We record an accrual for legal contingencies when we determine that it is probable that we have incurred a liability and we can reasonably estimate the amount of the loss. In making such determinations we evaluate, among other things, the probability of an unfavorable outcome and, when we believe it probable that a liability has been incurred, our ability to make a reasonable estimate of the loss. We review these accruals each reporting period and make revisions based on changes in facts and circumstances.
Business Combinations	We allocate the purchase price of an acquisition to the tangible and intangible assets acquired and liabilities assumed based on their estimated fair values at the acquisition date. We recognize as goodwill the amount by which the purchase price of an acquired entity exceeds the net of the fair values assigned to the assets acquired and liabilities assumed. In determining the fair values of assets acquired and liabilities assumed, we use various recognized valuation methods including the income and market approaches. Further, we make assumptions within certain valuation techniques, including discount rates, royalty rates, and the amount and timing of future cash flows. We record the net assets and results of operations of an acquired entity in our Financial Statements from the acquisition date. We initially perform these valuations based upon preliminary estimates and assumptions by management or independent valuation specialists under our supervision, where appropriate, and make revisions as estimates and assumptions are finalized. We expense acquisition-related costs as we incur them.
Asset Acquisitions	Acquisitions that do not meet the definition of a business are accounted for as asset acquisitions. We allocate the cost of the acquisition, including direct and incremental transaction costs, to the individual assets acquired and liabilities assumed on a relative fair value basis. Goodwill is not recognized in an asset acquisition. See Note 4 for additional information.
New Accounting Standards	New Accounting Standards Adopted ASU No. 2016-13 - “Financial Instruments-Credit Losses” (Topic 326). ASU 2016-13 requires the use of an impairment methodology that reflects an estimate of expected credit losses, measured over the contractual life of an instrument, based on information about past events, current conditions, and forecasts of future economic conditions. We adopted ASU 2016-13 in the 2020 first quarter using the modified retrospective transition method. Upon adoption, we increased our allowance for credit losses in the “Accounts and notes receivable, net” caption of our Balance Sheets by $19 million, from $82 million at December 31, 2019 to $101 million at January 1, 2020. We also recorded a $4 million decrease in the “Deferred tax liabilities” caption of our Balance Sheets and a $15 million cumulative-effect adjustment to retained earnings on our Balance Sheets.
Intangible Assets	We capitalize direct costs that we incur to obtain management, franchise, and license agreements. We amortize these costs on a straight-line basis over the initial term of the agreements, ranging from 15 to 30 years.
Property and Equipment, Capitalization and Useful Lives	We record property and equipment at cost, including interest and real estate taxes we incur during development and construction. We capitalize the cost of improvements that extend the useful life of property and equipment when we incur them. These capitalized costs may include structural costs, equipment, fixtures, floor, and wall coverings. We expense all repair and maintenance costs when we incur them. We compute depreciation using the straight-line method over the estimated useful lives of the assets (generally three

RESTRUCTURING CHARGES (Tables)

RESTRUCTURING CHARGES (Tables)	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring Reserve Activity	The following table presents our restructuring reserve activity during the period: ($ in millions) Employee termination benefits Balance at December 31, 2019 $ — Charges 366 Cash payments (215) Other (8) Balance at December 31, 2020, classified in “Accrued expenses and other” $ 143

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Reconciliation of the Earnings (Losses) and Number of Shares Used in Calculations of Basic and Diluted Earnings Per Share	The table below illustrates the reconciliation of the earnings and number of shares used in our calculations of basic and diluted earnings per share, the latter of which uses the treasury stock method in order to calculate the dilutive effect of the Company’s potential common stock: (in millions, except per share amounts) 2020 2019 2018 Computation of Basic (Loss) Earnings Per Share Net (loss) income $ (267) $ 1,273 $ 1,907 Shares for basic (loss) earnings per share 325.8 332.7 350.1 Basic (loss) earnings per share $ (0.82) $ 3.83 $ 5.45 Computation of Diluted (Loss) Earnings Per Share Net (loss) income $ (267) $ 1,273 $ 1,907 Shares for basic earnings per share 325.8 332.7 350.1 Effect of dilutive securities Stock-based compensation (1) — 2.8 4.1 Shares for diluted (loss) earnings per share 325.8 335.5 354.2 Diluted (loss) earnings per share $ (0.82) $ 3.80 $ 5.38 (1) For the calculation of diluted loss per share for year-end 2020, we excluded share-based compensation securities of 1.4 million because the effect was anti-dilutive.

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Additional Information on RSUs	The following table provides additional information on RSUs, including PSUs, for the last three fiscal years: 2020 2019 2018 Stock-based compensation expense (in millions) $ 188 $ 177 $ 170 Weighted average grant-date fair value (per RSU) $ 101 $ 117 $ 132 Aggregate intrinsic value of distributed RSUs (in millions) $ 234 $ 276 $ 294
Changes in Outstanding RSU Grants	The following table presents the changes in our outstanding RSUs, including PSUs, during 2020 and the associated weighted average grant-date fair values: Number of RSUs (in millions) Weighted Average Grant-Date Fair Value (per unit) Outstanding at year-end 2019 4.1 $ 106 Granted 3.6 101 Distributed (1.6) 97 Forfeited (0.3) 114 Outstanding at year-end 2020 5.8 $ 107

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of (Losses) Earnings Before Income Taxes	The components of our (losses) earnings before income taxes for the last three fiscal years consisted of: ($ in millions) 2020 2019 2018 U.S. $ (320) $ 549 $ 1,311 Non-U.S. (146) 1,050 1,034 $ (466) $ 1,599 $ 2,345
Benefit (Provision) for Income Taxes	Our benefit (provision) for income taxes for the last three fiscal years consisted of: ($ in millions) 2020 2019 2018 Current -U.S. Federal $ 9 $ (272) $ (169) -U.S. State (41) (57) (94) -Non-U.S. (78) (161) (284) (110) (490) (547) Deferred -U.S. Federal 180 141 10 -U.S. State 81 39 (6) -Non-U.S. 48 (16) 105 309 164 109 $ 199 $ (326) $ (438)
Unrecognized Tax Benefits Reconciliation	The following table reconciles our unrecognized tax benefit balance for each year from the beginning of 2018 to the end of 2020: ($ in millions) Amount Unrecognized tax benefit at beginning of 2018 $ 491 Change attributable to tax positions taken in prior years 37 Change attributable to tax positions taken during the current period 148 Decrease attributable to settlements with taxing authorities (53) Unrecognized tax benefit at year-end 2018 623 Change attributable to tax positions taken in prior years (13) Change attributable to tax positions taken during the current period 13 Decrease attributable to settlements with taxing authorities (54) Unrecognized tax benefit at year-end 2019 569 Change attributable to tax positions taken in prior years (66) Change attributable to tax positions taken during the current period 4 Decrease attributable to settlements with taxing authorities (43) Unrecognized tax benefit at year-end 2020 $ 464
Schedule of Deferred Tax Assets and Liabilities	The following table presents the tax effect of each type of temporary difference and carry-forward that gave rise to significant portions of our deferred tax assets and liabilities as of year-end 2020 and year-end 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Deferred Tax Assets Employee benefits $ 262 $ 267 Net operating loss carry-forwards 818 680 Accrued expenses and other reserves 214 162 Receivables, net 12 11 Tax credits 49 41 Loyalty Program 367 249 Deferred income 69 70 Lease liabilities 252 261 Other 82 15 Deferred tax assets 2,125 1,756 Valuation allowance (1,009) (616) Deferred tax assets after valuation allowance 1,116 1,140 Deferred Tax Liabilities Equity method investments (29) (55) Property and equipment (42) (82) Intangibles (663) (895) Right-of-use assets (197) (229) Self-insurance (19) (15) Deferred tax liabilities (950) (1,276) Net deferred taxes $ 166 $ (136)
Reconciliation of the U.S. Statutory Tax Rate to Effective Income Tax Rate	The following table reconciles the U.S. statutory tax rate to our effective income tax rate for the last three fiscal years: 2020 2019 2018 U.S. statutory tax rate 21.0 % 21.0 % 21.0 % U.S. state income taxes, net of U.S. federal tax benefit 3.8 1.6 2.5 Non-U.S. income 12.5 (3.3) (1.0) Change in valuation allowance (20.0) 3.4 2.6 Change in uncertain tax positions 12.2 1.9 1.0 Change in U.S. tax rate 0.0 0.0 (1.7) Permanent items 9.4 1.3 0.0 Tax on asset dispositions 0.0 (0.7) (2.9) Excess tax benefits related to equity awards 6.4 (3.2) (1.8) U.S. tax on foreign earnings (3.0) 0.1 0.0 Other, net 0.6 (1.7) (1.0) Effective rate 42.9 % 20.4 % 18.7 %

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Maximum Potential Amount of Future Fundings as the Primary Obligor for Guarantees and the Liability for Expected Future Fundings	We present the maximum potential amount of our future guarantee fundings and the carrying amount of our liability for our debt service, operating profit, and other guarantees (excluding contingent purchase obligations) for which we are the primary obligor at year-end 2020 in the following table: ($ in millions) Guarantee Type Maximum Potential Recorded Liability for Debt service $ 53 $ 6 Operating profit 207 128 Other 19 4 $ 279 $ 138

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Composition of Lease Expense and Supplemental Cash Flows	The following table details the composition of lease expense for 2020 and 2019: ($ in millions) 2020 2019 Operating lease cost $ 157 $ 185 Variable lease cost 60 113 The following table presents supplemental cash flow information for 2020 and 2019: ($ in millions) 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflows for operating leases $ 162 $ 176 Operating cash outflows for finance leases 7 7 Financing cash outflows for finance leases 6 6 Lease assets obtained in exchange for lease obligations: Operating leases 35 89
Maturities of Finance Lease Liabilities	The following table presents our future minimum lease payments at year-end 2020: ($ in millions) Operating Leases Finance Leases 2021 $ 184 $ 13 2022 176 13 2023 124 14 2024 116 14 2025 106 14 Thereafter 529 138 Total minimum lease payments $ 1,235 $ 206 Less: Amount representing interest 265 53 Present value of minimum lease payments $ 970 $ 153
Maturities of Operating Lease Liabilities	The following table presents our future minimum lease payments at year-end 2020: ($ in millions) Operating Leases Finance Leases 2021 $ 184 $ 13 2022 176 13 2023 124 14 2024 116 14 2025 106 14 Thereafter 529 138 Total minimum lease payments $ 1,235 $ 206 Less: Amount representing interest 265 53 Present value of minimum lease payments $ 970 $ 153
Assets And Liabilities, Lessee	The following table presents the composition of our current and noncurrent lease liability at year-end 2020 and 2019: ($ in millions) December 31, 2020 December 31, 2019 Operating Leases Finance Leases Operating Leases Finance Leases Current (1) $ 147 $ 7 $ 130 $ 6 Noncurrent (2) 823 146 882 151 $ 970 $ 153 $ 1,012 $ 157 (1) Operating leases are recorded in the “ Accrued expenses and other (2) Operating leases are recorded in the “Operating lease liabilities” and finance leases are recorded in the “Long-term debt” captions of our Balance Sheets.
Lease Terms and Discount Rate	The following table presents additional information about our lease obligations at year-end 2020 and 2019: 2020 2019 Operating leases Finance leases Operating leases Finance leases Weighted Average Remaining Lease Term (in years) 10 13 11 14 Weighted Average Discount Rate 4.6 % 4.4 % 4.8 % 4.4 %

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	We provide detail on our long-term debt balances, net of discounts, premiums, and debt issuance costs, in the following table at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Senior Notes: Series L Notes, interest rate of 3.3%, face amount of $173, maturing September 15, 2022 (effective interest rate of 3.4%) $ 173 $ 349 Series M Notes, interest rate of 3.4%, face amount of $350, matured October 15, 2020 (effective interest rate of 3.6%) — 349 Series N Notes, interest rate of 3.1%, face amount of $400, maturing October 15, 2021 (effective interest rate of 3.4%) 399 398 Series O Notes, interest rate of 2.9%, face amount of $450, maturing March 1, 2021 (effective interest rate of 3.1%) 450 449 Series P Notes, interest rate of 3.8%, face amount of $350, maturing October 1, 2025 (effective interest rate of 4.0%) 346 346 Series Q Notes, interest rate of 2.3%, face amount of $399, maturing January 15, 2022 (effective interest rate of 2.5%) 398 747 Series R Notes, interest rate of 3.1%, face amount of $750, maturing June 15, 2026 (effective interest rate of 3.3%) 745 744 Series U Notes, interest rate of 3.1%, face amount of $291, maturing February 15, 2023 (effective interest rate of 3.1%) 291 291 Series V Notes, interest rate of 3.8%, face amount of $318, maturing March 15, 2025 (effective interest rate of 2.8%) 330 332 Series W Notes, interest rate of 4.5%, face amount of $278, maturing October 1, 2034 (effective interest rate of 4.1%) 290 291 Series X Notes, interest rate of 4.0%, face amount of $450, maturing April 15, 2028 (effective interest rate of 4.2%) 445 444 Series Y Notes, floating rate, face amount of $550, matured December 1, 2020 — 549 Series Z Notes, interest rate of 4.2%, face amount of $350, maturing December 1, 2023 (effective interest rate of 4.4%) 348 347 Series AA Notes, interest rate of 4.7%, face amount of $300, maturing December 1, 2028 (effective interest rate of 4.8%) 297 297 Series BB Notes, floating rate, face amount of $300, maturing March 8, 2021 (effective interest rate of 0.9% at December 31, 2020) 300 299 Series CC Notes, interest rate of 3.6%, face amount of $550, maturing April 15, 2024 (effective interest rate of 3.9%) 586 564 Series DD Notes, interest rate of 2.1%, face amount of $224, maturing October 3, 2022 (effective interest rate of 1.2%) 228 543 Series EE Notes, interest rate of 5.8%, face amount of $1,600, maturing May 1, 2025 (effective interest rate of 6.0%) 1,583 — Series FF Notes, interest rate of 4.6%, face amount of $1,000, maturing June 15, 2030 (effective interest rate of 4.8%) 986 — Series GG Notes, interest rate of 3.5%, face amount of $1,000, maturing October 15, 2032 (effective interest rate of 3.7%) 985 — Commercial paper — 3,197 Credit Facility 900 — Finance lease obligations 153 157 Other 143 247 $ 10,376 $ 10,940 Less current portion (1,173) (977) $ 9,203 $ 9,963
Future Principal Payments for Debt	The following table presents future principal payments, net of discounts, premiums, and debt issuance costs, for our debt at year-end 2020: Debt Principal Payments ($ in millions) Amount 2021 $ 1,173 2022 807 2023 682 2024 1,494 2025 2,302 Thereafter 3,918 Balance at year-end 2020 $ 10,376

INTANGIBLE ASSETS AND GOODWILL

INTANGIBLE ASSETS AND GOODWILL (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Composition of Intangible Assets, Finite-Lived	The following table details the composition of our intangible assets at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Definite-lived Intangible Assets Costs incurred to obtain contracts with customers $ 1,674 $ 1,588 Contracts acquired in business combinations and other 2,257 1,972 3,931 3,560 Accumulated amortization (937) (808) 2,994 2,752 Indefinite-lived Intangible Brand Assets 5,995 5,889 $ 8,989 $ 8,641
Composition of Intangible Assets, Indefinite-Lived	The following table details the composition of our intangible assets at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Definite-lived Intangible Assets Costs incurred to obtain contracts with customers $ 1,674 $ 1,588 Contracts acquired in business combinations and other 2,257 1,972 3,931 3,560 Accumulated amortization (937) (808) 2,994 2,752 Indefinite-lived Intangible Brand Assets 5,995 5,889 $ 8,989 $ 8,641
Carrying Amount of Goodwill	The following table details the carrying amount of our goodwill at year-end 2020 and 2019: ($ in millions) U.S. & Canada Asia Pacific EMEA CALA Total Balance at year-end 2019 $ 5,338 $ 1,864 $ 1,522 $ 324 $ 9,048 Foreign currency translation 9 71 57 (10) 127 Balance at year-end 2020 $ 5,347 $ 1,935 $ 1,579 $ 314 $ 9,175

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Composition of Property and Equipment Balances	The following table presents the composition of our property and equipment balances at year-end 2020 and 2019: ($ in millions) At Year-End 2020 At Year-End 2019 Land $ 688 $ 684 Buildings and leasehold improvements 1,045 1,100 Furniture and equipment 640 1,225 Construction in progress 29 196 2,402 3,205 Accumulated depreciation (888) (1,301) $ 1,514 $ 1,904

FAIR VALUE OF FINANCIAL INSTR_2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Carrying Values and Fair Values of Non-Current Financial Assets and Liabilities	We present the carrying values and the fair values of noncurrent financial assets and liabilities that qualify as financial instruments, determined under current guidance for disclosures on the fair value of financial instruments, in the following table: At Year-End 2020 At Year-End 2019 ($ in millions) Carrying Fair Value Carrying Fair Value Senior, mezzanine, and other loans $ 159 $ 142 $ 117 $ 112 Total noncurrent financial assets $ 159 $ 142 $ 117 $ 112 Senior Notes $ (8,031) $ (8,941) $ (6,441) $ (6,712) Commercial paper/Credit Facility (900) (900) (3,197) (3,197) Other long-term debt (126) (128) (174) (179) Other noncurrent liabilities (426) (426) (196) (196) Total noncurrent financial liabilities $ (9,483) $ (10,395) $ (10,008) $ (10,284)

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Accumulated Other Comprehensive (Loss) Income Activity	The following table details the accumulated other comprehensive loss activity for 2020, 2019, and 2018: ($ in millions) Foreign Currency Translation Adjustments Derivative Instrument and Other Adjustments Accumulated Other Comprehensive Loss Balance at year-end 2017 $ (23) $ 6 $ (17) Other comprehensive (loss) income before reclassifications (1) (391) 4 (387) Reclassification adjustments 11 6 17 Net other comprehensive (loss) income (380) 10 (370) Adoption of ASU 2016-01 — (4) (4) Balance at year-end 2018 $ (403) $ 12 $ (391) Other comprehensive income before reclassifications (1) 35 2 37 Reclassification adjustments — (7) (7) Net other comprehensive income (loss) 35 (5) 30 Balance at year-end 2019 $ (368) $ 7 $ (361) Other comprehensive income before reclassifications (1) 229 7 236 Reclassification adjustments — (10) (10) Net other comprehensive income (loss) 229 (3) 226 Balance at year-end 2020 $ (139) $ 4 $ (135) (1) Other comprehensive (loss) income before reclassifications for foreign currency translation adjustments includes intra-entity foreign currency transactions that are of a long-term investment nature, which resulted in (losses) gains of $(44) million for 2020, $6 million for 2019, and $14 million for 2018.

BUSINESS SEGMENTS (Tables)

BUSINESS SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Segment Revenues	Segment Revenues The following tables present our revenues disaggregated by segment and major revenue stream for the last three fiscal years: 2020 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 914 $ 183 $ 110 $ 1,207 Contract investment amortization (108) (7) (12) (127) Net fee revenues 806 176 98 1,080 Owned, leased, and other revenue 198 89 153 440 Cost reimbursement revenue 6,901 347 507 7,755 Total reportable segment revenue $ 7,905 $ 612 $ 758 $ 9,275 Unallocated corporate and other 1,296 Total revenue $ 10,571 2019 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 2,265 $ 477 $ 418 $ 3,160 Contract investment amortization (48) (2) (8) (58) Net fee revenues 2,217 475 410 3,102 Owned, leased, and other revenue 715 178 553 1,446 Cost reimbursement revenue 13,901 536 969 15,406 Total reportable segment revenue $ 16,833 $ 1,189 $ 1,932 $ 19,954 Unallocated corporate and other 1,018 Total revenue $ 20,972 2018 ($ in millions) U.S. & Canada Asia Pacific EMEA Total Gross fee revenues $ 2,158 $ 479 $ 387 $ 3,024 Contract investment amortization (45) (2) (7) (54) Net fee revenues 2,113 477 380 2,970 Owned, leased, and other revenue 721 182 563 1,466 Cost reimbursement revenue 13,455 459 926 14,840 Total reportable segment revenue $ 16,289 $ 1,118 $ 1,869 $ 19,276 Unallocated corporate and other 1,482 Total revenue $ 20,758
Segment Profits	Segment Profits and Losses ($ in millions) 2020 2019 2018 U.S. & Canada (1) $ 198 $ 2,000 $ 1,939 Asia Pacific (2) 1 369 456 EMEA (3) (200) 318 328 Unallocated corporate and other (47) (720) (60) Interest expense, net of interest income (418) (368) (318) Benefit (provision) for income taxes 199 (326) (438) Net (loss) income $ (267) $ 1,273 $ 1,907 (1) Includes cost reimbursements, net of $(80) million in 2020, $(129) million in 2019, and $(121) million in 2018. (2) Includes cost reimbursements, net of $(18) million in 2020, $(9) million in 2019, and zero in 2018. (3) Includes cost reimbursements, net of $(33) million in 2020, $(8) million in 2019, and zero in 2018.
Depreciation and Amortization	Depreciation, Amortization, and Other ($ in millions) 2020 2019 2018 U.S. & Canada $ 209 $ 218 $ 97 Asia Pacific 30 25 26 EMEA 58 51 51 Unallocated corporate and other 49 47 52 $ 346 $ 341 $ 226
Capital Expenditures	Capital Expenditures ($ in millions) 2020 2019 2018 U.S. & Canada $ 12 $ 287 $ 305 Asia Pacific 2 2 6 EMEA 12 29 36 Unallocated corporate and other 109 335 209 $ 135 $ 653 $ 556

RELATED PARTY TRANSACTIONS (Tab

RELATED PARTY TRANSACTIONS (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Financial Data Resulting from Transactions with Related Parties, Income Statement Data	The following table presents Income Statement data resulting from transactions with these related parties. This table does not include our Financial Statement captions with insignificant related party activity. ($ in millions) 2020 2019 2018 Cost reimbursement revenue $ 107 $ 233 $ 332 Reimbursed expenses (110) (236) (337) Equity in (losses) earnings (141) 13 103
Summarized Information for the Entities Equity Method Investments, Income Statement	The following tables present summarized financial information for the entities in which we have equity method investments: ($ in millions) 2020 2019 2018 Sales $ 259 $ 815 $ 932 Net (loss) income (212) 80 221
Summarized Information for the Entities Equity Method Investments, Balance Sheet	($ in millions) At Year-End 2020 At Year-End 2019 Assets (primarily composed of hotel real estate managed by us) $ 2,348 $ 2,555 Liabilities 1,623 1,691

SUPPLEMENTARY DATA QUARTERLY _2

SUPPLEMENTARY DATA QUARTERLY FINANCIAL DATA - UNAUDITED (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	($ in millions, except per share data) 2020 First Second Third Fourth Fiscal Revenues $ 4,681 $ 1,464 $ 2,254 $ 2,172 $ 10,571 Operating income (loss) $ 114 $ (154) $ 252 $ (128) $ 84 Net income (loss) $ 31 $ (234) $ 100 $ (164) $ (267) Basic earnings (loss) per share (1) $ 0.10 $ (0.72) $ 0.31 $ (0.50) $ (0.82) Diluted earnings (loss) per share (1) $ 0.09 $ (0.72) $ 0.31 $ (0.50) $ (0.82) ($ in millions, except per share data) 2019 First Second Third Fourth Fiscal Revenues $ 5,012 $ 5,305 $ 5,284 $ 5,371 $ 20,972 Operating income $ 510 $ 409 $ 607 $ 274 $ 1,800 Net income $ 375 $ 232 $ 387 $ 279 $ 1,273 Basic earnings per share (1) $ 1.10 $ 0.70 $ 1.17 $ 0.85 $ 3.83 Diluted earnings per share (1) $ 1.09 $ 0.69 $ 1.16 $ 0.85 $ 3.80 (1) The sum of the earnings per share for the four quarters may differ from annual earnings per share due to the required method of computing the weighted average shares in interim periods.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)		1 Months Ended	3 Months Ended								12 Months Ended
		May 31, 2020USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2020USD ($)
Significant Accounting Policies [Line Items]
Revenues			$ 2,172,000,000	$ 2,254,000,000	$ 1,464,000,000	$ 4,681,000,000	$ 5,371,000,000	$ 5,284,000,000	$ 5,305,000,000	$ 5,012,000,000	$ 10,571,000,000	$ 20,972,000,000	$ 20,758,000,000
Compensation costs from retirement savings plan											75,000,000	128,000,000	224,000,000
Advertising costs											276,000,000	851,000,000	660,000,000
Goodwill impairment charge											0	0	0
Self-insurance reserve, current			121,000,000				166,000,000				121,000,000	166,000,000
Self-insurance reserve, noncurrent			341,000,000				323,000,000				341,000,000	323,000,000
Allowance for credit losses			207,000,000				82,000,000				207,000,000	82,000,000			$ 101,000,000
Deferred tax liabilities			83,000,000				290,000,000				83,000,000	290,000,000
Equity			430,000,000				703,000,000				430,000,000	703,000,000	2,225,000,000	$ 3,582,000,000
Change in allowance for credit losses											136,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Significant Accounting Policies [Line Items]
Gain (loss) on disposal													132,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Avendra LLC
Significant Accounting Policies [Line Items]
Gain (loss) on disposal														664,000,000
Gain (loss) on disposal, net of tax														425,000,000
Retained Earnings
Significant Accounting Policies [Line Items]
Equity			$ 9,206,000,000				9,644,000,000				$ 9,206,000,000	9,644,000,000	8,982,000,000	$ 7,242,000,000
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13
Significant Accounting Policies [Line Items]
Allowance for credit losses															19,000,000
Deferred tax liabilities															(4,000,000)
Equity							(15,000,000)					(15,000,000)
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 | Retained Earnings
Significant Accounting Policies [Line Items]
Equity							(15,000,000)					(15,000,000)			$ 15,000,000
Measurement Input, Discount Rate | Valuation Technique, Discounted Cash Flow
Significant Accounting Policies [Line Items]
Self insurance review, measurement input			0.02								0.02
Deferred revenue
Significant Accounting Policies [Line Items]
Change in customer contract liability											$ 907,000,000
Customer contract liability			$ 1,867,000,000				960,000,000				1,867,000,000	960,000,000
Guest loyalty program
Significant Accounting Policies [Line Items]
Change in customer contract liability											553,000,000
Customer contract liability			6,271,000,000				5,718,000,000				6,271,000,000	5,718,000,000
Revenue recognized from customer contract liability											1,118,000,000
Change in customer contract liability from change in estimates											(47,000,000)
Change in customer contract liability from prepayment		$ 920,000,000
Reimbursements
Significant Accounting Policies [Line Items]
Revenues	[1]										8,452,000,000	15,599,000,000	15,543,000,000
Reimbursements | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Avendra LLC
Significant Accounting Policies [Line Items]
Revenues											62,000,000	118,000,000	115,000,000
Revenues, net of tax											46,000,000	87,000,000	$ 85,000,000
Costs Incurred to Fulfill Contracts
Significant Accounting Policies [Line Items]
Capitalized costs			$ 366,000,000				$ 351,000,000				$ 366,000,000	$ 351,000,000
[1]	See Note 16 for disclosure of related party amounts.

RESTRUCTURING CHARGES - Narrati

RESTRUCTURING CHARGES - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Restructuring Cost and Reserve [Line Items]
Charges	$ 366
U.S. & Canada
Restructuring Cost and Reserve [Line Items]
Charges	255
Global Above-Property Positions
Restructuring Cost and Reserve [Line Items]
Charges	117
Property-Level and Owned and Leased Properties
Restructuring Cost and Reserve [Line Items]
Charges	249
Restructuring and merger-related charges
Restructuring Cost and Reserve [Line Items]
Charges	56
Restructuring and merger-related charges | Global Above-Property Positions
Restructuring Cost and Reserve [Line Items]
Charges	44
Restructuring and merger-related charges | Property-Level and Owned and Leased Properties
Restructuring Cost and Reserve [Line Items]
Charges	12
Reimbursed expenses
Restructuring Cost and Reserve [Line Items]
Charges	310
Reimbursed expenses | Global Above-Property Positions
Restructuring Cost and Reserve [Line Items]
Charges	73
Reimbursed expenses | Property-Level and Owned and Leased Properties
Restructuring Cost and Reserve [Line Items]
Charges	$ 237

RESTRUCTURING CHARGES - Rollfor

RESTRUCTURING CHARGES - Rollforward of Reserves (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Restructuring Reserve [Roll Forward]
Charges	$ 366
Employee termination benefits
Restructuring Reserve [Roll Forward]
Beginning balance	0
Charges	366
Cash payments	(215)
Other	(8)
Ending balance	$ 143

DISPOSITIONS AND ACQUISITIONS -

DISPOSITIONS AND ACQUISITIONS - Disposals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)property	Dec. 31, 2018USD ($)propertyinvestment	Dec. 31, 2020USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of equity method investments disposed | investment		3
Gain on disposal of equity method investment		$ 42
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal		$ 132
Disposal Group, Disposed of by Sale, Not Discontinued Operations | U.S. and Canada Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration for property sold			$ 268
Gain (loss) on disposal	$ 134
Number of properties disposed | property	2	2
Gain on disposal from equity method investee		$ 10
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Asia Pacific Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties disposed | property		2
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Caribbean and Latin America Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties disposed | property		2
Gain on disposal from equity method investee		$ 55

DISPOSITIONS AND ACQUISITIONS_2

DISPOSITIONS AND ACQUISITIONS - Acquisitions (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)jointVenturehotel
Elegant Hotels Group plc
Schedule of Asset Acquisition [Line Items]
Property purchased	$ 128
Debt assumed	$ 63
Number of properties acquired | hotel	7
U.S. and Canada Properties
Schedule of Asset Acquisition [Line Items]
Property purchased	$ 206
AC Hotels by Marriott
Schedule of Asset Acquisition [Line Items]
Number of joint ventures acquired | jointVenture	2
AC Hotels by Marriott | Management and Franchise Contracts
Schedule of Asset Acquisition [Line Items]
Finite lived intangible assets acquired	24 years
Finite lived intangible assets term	$ 34
AC Hotels by Marriott | Brand Asset
Schedule of Asset Acquisition [Line Items]
Indefinite lived intangible assets acquired	$ 156

EARNINGS PER SHARE - Reconcilia

EARNINGS PER SHARE - Reconciliation of the Earnings (Losses) and Number of Shares Used in Calculations of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Computation of Basic (Loss) Earnings Per Share
Net (loss) income	$ (164)	$ 100	$ (234)	$ 31	$ 279	$ 387	$ 232	$ 375	$ (267)	$ 1,273	$ 1,907
Shares for basic (loss) earnings per share (in shares)									325.8	332.7	350.1
Basic (loss) earnings per share (in USD per share)	$ (0.50)	$ 0.31	$ (0.72)	$ 0.10	$ 0.85	$ 1.17	$ 0.70	$ 1.10	$ (0.82)	$ 3.83	$ 5.45
Computation of Diluted (Loss) Earnings Per Share
Net (loss) income	$ (164)	$ 100	$ (234)	$ 31	$ 279	$ 387	$ 232	$ 375	$ (267)	$ 1,273	$ 1,907
Shares for basic earnings per share (in shares)									325.8	332.7	350.1
Effect of dilutive securities
Stock-based compensation (in shares)									0	2.8	4.1
Shares for diluted (loss) earnings per share (in shares)									325.8	335.5	354.2
Diluted (loss) earnings per share (in USD per share)	$ (0.50)	$ 0.31	$ (0.72)	$ 0.09	$ 0.85	$ 1.16	$ 0.69	$ 1.09	$ (0.82)	$ 3.80	$ 5.38
Antidilutive shares (in shares)									1.4

STOCK-BASED COMPENSATION - Addi

STOCK-BASED COMPENSATION - Additional Information (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved under the stock plan (in shares)	27
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Period of service after grant date	1 year
Deferred compensation costs	$ 301	$ 176
Weighted average remaining term for grants outstanding	2 years 6 months
PSUs | Certain Executive Officers
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years

STOCK-BASED COMPENSATION - Ad_2

STOCK-BASED COMPENSATION - Additional Information on RSUs (Details) - RSUs - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Restricted Stock Activity [Line Items]
Stock-based compensation expense (in millions)	$ 188	$ 177	$ 170
Weighted average grant-date fair value (in USD per share)	$ 101	$ 117	$ 132
Aggregate intrinsic value of distributed RSUs (in millions)	$ 234	$ 276	$ 294

STOCK-BASED COMPENSATION - Chan

STOCK-BASED COMPENSATION - Changes in Outstanding RSU Grants (Details) - RSUs - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of RSUs (in millions)
Outstanding beginning balance (in shares)	4.1
Granted (in shares)	3.6
Distributed (in shares)	(1.6)
Forfeited (in shares)	(0.3)
Outstanding ending balance (in shares)	5.8	4.1
Weighted Average Grant-Date Fair Value (per unit)
Outstanding beginning balance (in USD per share)	$ 106
Granted (in USD per share)	101	$ 117	$ 132
Distributed (in USD per share)	97
Forfeited (in USD per share)	114
Outstanding ending balance (in USD per share)	$ 107	$ 106

INCOME TAXES - Components of Ea

INCOME TAXES - Components of Earnings Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S.	$ (320)	$ 549	$ 1,311
Non-U.S.	(146)	1,050	1,034
(LOSS) INCOME BEFORE INCOME TAXES	$ (466)	$ 1,599	$ 2,345

INCOME TAXES - Provision for In

INCOME TAXES - Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
-U.S. Federal	$ 9	$ (272)	$ (169)
-U.S. State	(41)	(57)	(94)
-Non-U.S.	(78)	(161)	(284)
Current income tax expense	(110)	(490)	(547)
Deferred
-U.S. Federal	180	141	10
-U.S. State	81	39	(6)
-Non-U.S.	48	(16)	105
Deferred income tax expense	309	164	109
Provision for income taxes	$ 199	$ (326)	$ (438)

INCOME TAXES - Unrecognized Tax

INCOME TAXES - Unrecognized Tax Benefit Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit at beginning of year	$ 569	$ 623	$ 491
Change attributable to tax positions taken in prior years			37
Change attributable to tax positions taken in prior years	(66)	(13)
Change attributable to tax positions taken during the current period	4	13	148
Decrease attributable to settlements with taxing authorities	(43)	(54)	(53)
Unrecognized tax benefit at end of year	$ 464	$ 569	$ 623

INCOME TAXES - Additional Infor

INCOME TAXES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Unrecognized tax benefits that, if recognized, would impact the effective tax rate	$ 410	$ 498	$ 497
Interest and penalties related to unrecognized tax benefits	85	100
Interest related to unrecognized tax benefits	(15)	28	$ 3
Tax credits which expire	31
Tax credits which do not expire	17
Net operating loss benefits	44	$ 10
Net operating losses	3,938
Net operating losses subject to expiration	$ 2,315
Income tax benefit from non-U.S. income	12.50%	(3.30%)	(1.00%)
Pre-tax income	$ (146)	$ 1,050	$ 1,034
Income tax expense (benefit)	42.90%	20.40%	18.70%
Cash paid for income taxes	$ 279	$ 526	$ 678
Switzerland, Singapore, and Luxembourg
Income Tax Contingency [Line Items]
Income tax benefit from non-U.S. income	12.90%	8.80%	4.00%
Pre-tax income	$ 314	$ 709	$ 513
International
Income Tax Contingency [Line Items]
Income tax expense (benefit)			1.40%
International | United States
Income Tax Contingency [Line Items]
Income tax expense (benefit)	0.80%	2.00%

INCOME TAXES - Types of Tempora

INCOME TAXES - Types of Temporary Differences and Carry-Forwards that Significantly Effect Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets
Employee benefits	$ 262	$ 267
Net operating loss carry-forwards	818	680
Accrued expenses and other reserves	214	162
Receivables, net	12	11
Tax credits	49	41
Loyalty Program	367	249
Deferred income	69	70
Lease liabilities	252	261
Other	82	15
Deferred tax assets	2,125	1,756
Valuation allowance	(1,009)	(616)
Deferred tax assets after valuation allowance	1,116	1,140
Deferred Tax Liabilities
Equity method investments	(29)	(55)
Property and equipment	(42)	(82)
Intangibles	(663)	(895)
Right-of-use assets	(197)	(229)
Self-insurance	(19)	(15)
Deferred tax liabilities	(950)	(1,276)
Net deferred taxes	$ 166
Net deferred taxes		$ (136)

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of the U.S. Statutory Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. statutory tax rate	21.00%	21.00%	21.00%
U.S. state income taxes, net of U.S. federal tax benefit	3.80%	1.60%	2.50%
Non-U.S. income	12.50%	(3.30%)	(1.00%)
Change in valuation allowance	(20.00%)	3.40%	2.60%
Change in uncertain tax positions	12.20%	1.90%	1.00%
Change in U.S. tax rate	0.00%	0.00%	(1.70%)
Permanent items	9.40%	1.30%	0.00%
Tax on asset dispositions	0.00%	(0.70%)	(2.90%)
Excess tax benefits related to equity awards	6.40%	(3.20%)	(1.80%)
U.S. tax on foreign earnings	(0.030)	0.001	0
Other, net	0.60%	(1.70%)	(1.00%)
Effective rate	42.90%	20.40%	18.70%

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Guarantees (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	$ 279
Recorded Liability for Guarantees	138
Debt service
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	53
Recorded Liability for Guarantees	6
Operating profit
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	207
Recorded Liability for Guarantees	128
Other
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	19
Recorded Liability for Guarantees	4
Sheraton Grand Chicago Hotel
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	300	$ 57
Sheraton Grand Chicago Hotel | Land and Hotel
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings			$ 300
Sheraton Grand Chicago Hotel | Land
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings			$ 200
Not Yet In Effect Condition | Operating profit
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	90
Not Yet In Effect Condition | Other
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	7
Accrued Expenses and Other
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	16
Other noncurrent liabilities
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	$ 122
Minimum
Commitments and Contingencies Disclosure [Line Items]
Guarantee obligations, term	3 years
Maximum
Commitments and Contingencies Disclosure [Line Items]
Guarantee obligations, term	10 years

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Commitments (Details) £ in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2020GBP (£)	Mar. 15, 2019lawsuit	Dec. 31, 2020USD ($)lawsuit	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jul. 31, 2019GBP (£)
Commitments and Contingencies Disclosure [Line Items]
Purchase obligation			$ 437
Purchase obligation, expected to fund commitments in 2021			186
Purchase obligation, expected to fund commitments in 2022			137
Purchase obligation, expected to fund commitments in 2023			48
Purchase obligation, expected to fund commitments after 2023			66
Letters of credit outstanding			156
Surety bonds issued			163
Data Security Incident
Commitments and Contingencies Disclosure [Line Items]
Expense related to data security incident			(11)	$ 148	$ 28
Insurance recoveries			29	84	$ 25
Proceeds from insurance recoveries			47	58
Data Security Incident, UK Information Commissioner's Office
Commitments and Contingencies Disclosure [Line Items]
Expense related to data security incident			(39)	65
Estimated fine | £						£ 99
Fine | £	£ 18.4
Payment period for fine	2 years
Accrual for loss contingency			$ 17	$ 65
Putative Class Action Lawsuits Related to Data Security Incident
Commitments and Contingencies Disclosure [Line Items]
Number of lawsuits filed | lawsuit			100
Shareholder Derivative Complaints Related to Data Security Incident
Commitments and Contingencies Disclosure [Line Items]
Number of new lawsuits filed | lawsuit		2

LEASES - Additional Information

LEASES - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)renewal_option	Dec. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Lease term	20 years
Number of renewals (or more than) | renewal_option	1
Term of lease not commenced	20 years
U.S. and Canada Leased Hotels
Lessee, Lease, Description [Line Items]
Impairment loss	$ 116	$ 99
Legacy-Starwood Office Building
Lessee, Lease, Description [Line Items]
Impairment loss from building accounted for as a finance lease		$ 34
Minimum
Lessee, Lease, Description [Line Items]
Renewal term	5 years
Maximum
Lessee, Lease, Description [Line Items]
Renewal term	10 years

LEASES - Composition of Lease E

LEASES - Composition of Lease Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 157	$ 185
Variable lease cost	$ 60	$ 113

LEASES - Future Minimum Lease P

LEASES - Future Minimum Lease Payments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
2021	$ 184
2022	176
2023	124
2024	116
2025	106
Thereafter	529
Total minimum lease payments	1,235
Less: Amount representing interest	265
Present value of minimum lease payments	970	$ 1,012
Finance Leases
2021	13
2022	13
2023	14
2024	14
2025	14
Thereafter	138
Total minimum lease payments	206
Less: Amount representing interest	53
Finance lease obligations	$ 153	$ 157

LEASES - Currrent and Noncurren

LEASES - Currrent and Noncurrent Lease Liability (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
Current	$ 147	$ 130
Noncurrent	823	882
Present value of minimum lease payments	970	1,012
Finance Lease Liability [Abstract]
Current	7	6
Noncurrent	146	151
Present value of minimum lease payments	$ 153	$ 157
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations

LEASES - Lease Terms and Discou

LEASES - Lease Terms and Discount Rate (Details)	Dec. 31, 2020	Dec. 31, 2019
Weighted Average Remaining Lease Term (in years)
Operating leases	10 years	11 years
Finance leases	13 years	14 years
Weighted Average Discount Rate
Operating leases	4.60%	4.80%
Finance leases	4.40%	4.40%

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flows Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows for operating leases	$ 162	$ 176
Operating cash outflows for finance leases	7	7
Financing cash outflows for finance leases	6	6
Lease assets obtained in exchange for lease obligations:
Operating leases	$ 35	$ 89

LONG-TERM DEBT - Detail on Long

LONG-TERM DEBT - Detail on Long-term Debt Balances (Details) - USD ($)	Dec. 31, 2020	Sep. 30, 2020	Aug. 31, 2020	Jun. 30, 2020	Apr. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Commercial paper	$ 0					$ 3,197,000,000
Credit Facility	900,000,000					0
Finance lease obligations	153,000,000					157,000,000
Other	143,000,000					247,000,000
Long-term debt	10,376,000,000					10,940,000,000
Less current portion	(1,173,000,000)					(977,000,000)
Long-term debt, noncurrent	9,203,000,000					9,963,000,000
Series L Notes, interest rate of 3.3%, face amount of $173, maturing September 15, 2022 (effective interest rate of 3.4%)
Debt Instrument [Line Items]
Senior Notes	$ 173,000,000					349,000,000
Series L Notes, interest rate of 3.3%, face amount of $173, maturing September 15, 2022 (effective interest rate of 3.4%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.30%	3.30%
Senior notes, face amount	$ 173,000,000
Senior notes, effective interest rate	3.40%
Series M Notes, interest rate of 3.4%, face amount of $350, matured October 15, 2020 (effective interest rate of 3.6%)
Debt Instrument [Line Items]
Senior Notes	$ 0					349,000,000
Series M Notes, interest rate of 3.4%, face amount of $350, matured October 15, 2020 (effective interest rate of 3.6%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.40%
Senior notes, face amount	$ 350,000,000
Senior notes, effective interest rate	3.60%
Series N Notes, interest rate of 3.1%, face amount of $400, maturing October 15, 2021 (effective interest rate of 3.4%)
Debt Instrument [Line Items]
Senior Notes	$ 399,000,000					398,000,000
Series N Notes, interest rate of 3.1%, face amount of $400, maturing October 15, 2021 (effective interest rate of 3.4%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.10%
Senior notes, face amount	$ 400,000,000
Senior notes, effective interest rate	3.40%
Series O Notes, interest rate of 2.9%, face amount of $450, maturing March 1, 2021 (effective interest rate of 3.1%)
Debt Instrument [Line Items]
Senior Notes	$ 450,000,000					449,000,000
Series O Notes, interest rate of 2.9%, face amount of $450, maturing March 1, 2021 (effective interest rate of 3.1%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	2.90%
Senior notes, face amount	$ 450,000,000
Senior notes, effective interest rate	3.10%
Series P Notes, interest rate of 3.8%, face amount of $350, maturing October 1, 2025 (effective interest rate of 4.0%)
Debt Instrument [Line Items]
Senior Notes	$ 346,000,000					346,000,000
Series P Notes, interest rate of 3.8%, face amount of $350, maturing October 1, 2025 (effective interest rate of 4.0%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.80%
Senior notes, face amount	$ 350,000,000
Senior notes, effective interest rate	4.00%
Series Q Notes, interest rate of 2.3%, face amount of $399, maturing January 15, 2022 (effective interest rate of 2.5%)
Debt Instrument [Line Items]
Senior Notes	$ 398,000,000					747,000,000
Series Q Notes, interest rate of 2.3%, face amount of $399, maturing January 15, 2022 (effective interest rate of 2.5%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	2.30%	2.30%
Senior notes, face amount	$ 399,000,000
Senior notes, effective interest rate	2.50%
Series R Notes, interest rate of 3.1%, face amount of $750, maturing June 15, 2026 (effective interest rate of 3.3%)
Debt Instrument [Line Items]
Senior Notes	$ 745,000,000					744,000,000
Series R Notes, interest rate of 3.1%, face amount of $750, maturing June 15, 2026 (effective interest rate of 3.3%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.10%
Senior notes, face amount	$ 750,000,000
Senior notes, effective interest rate	3.30%
Series U Notes, interest rate of 3.1%, face amount of $291, maturing February 15, 2023 (effective interest rate of 3.1%)
Debt Instrument [Line Items]
Senior Notes	$ 291,000,000					291,000,000
Series U Notes, interest rate of 3.1%, face amount of $291, maturing February 15, 2023 (effective interest rate of 3.1%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.10%
Senior notes, face amount	$ 291,000,000
Senior notes, effective interest rate	3.10%
Series V Notes, interest rate of 3.8%, face amount of $318, maturing March 15, 2025 (effective interest rate of 2.8%)
Debt Instrument [Line Items]
Senior Notes	$ 330,000,000					332,000,000
Series V Notes, interest rate of 3.8%, face amount of $318, maturing March 15, 2025 (effective interest rate of 2.8%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.80%
Senior notes, face amount	$ 318,000,000
Senior notes, effective interest rate	2.80%
Series W Notes, interest rate of 4.5%, face amount of $278, maturing October 1, 2034 (effective interest rate of 4.1%)
Debt Instrument [Line Items]
Senior Notes	$ 290,000,000					291,000,000
Series W Notes, interest rate of 4.5%, face amount of $278, maturing October 1, 2034 (effective interest rate of 4.1%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	4.50%
Senior notes, face amount	$ 278,000,000
Senior notes, effective interest rate	4.10%
Series X Notes, interest rate of 4.0%, face amount of $450, maturing April 15, 2028 (effective interest rate of 4.2%)
Debt Instrument [Line Items]
Senior Notes	$ 445,000,000					444,000,000
Series X Notes, interest rate of 4.0%, face amount of $450, maturing April 15, 2028 (effective interest rate of 4.2%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	4.00%
Senior notes, face amount	$ 450,000,000
Senior notes, effective interest rate	4.20%
Series Y Notes, floating rate, face amount of $550, matured December 1, 2020
Debt Instrument [Line Items]
Senior Notes	$ 0					549,000,000
Series Y Notes, floating rate, face amount of $550, matured December 1, 2020 | Senior Notes
Debt Instrument [Line Items]
Senior notes, face amount	550,000,000
Series Z Notes, interest rate of 4.2%, face amount of $350, maturing December 1, 2023 (effective interest rate of 4.4%)
Debt Instrument [Line Items]
Senior Notes	$ 348,000,000					347,000,000
Series Z Notes, interest rate of 4.2%, face amount of $350, maturing December 1, 2023 (effective interest rate of 4.4%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	4.20%
Senior notes, face amount	$ 350,000,000
Senior notes, effective interest rate	4.40%
Series AA Notes, interest rate of 4.7%, face amount of $300, maturing December 1, 2028 (effective interest rate of 4.8%)
Debt Instrument [Line Items]
Senior Notes	$ 297,000,000					297,000,000
Series AA Notes, interest rate of 4.7%, face amount of $300, maturing December 1, 2028 (effective interest rate of 4.8%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	4.70%
Senior notes, face amount	$ 300,000,000
Senior notes, effective interest rate	4.80%
Series BB Notes, floating rate, face amount of $300, maturing March 8, 2021 (effective interest rate of 0.9% at December 31, 2020)
Debt Instrument [Line Items]
Senior Notes	$ 300,000,000					299,000,000
Series BB Notes, floating rate, face amount of $300, maturing March 8, 2021 (effective interest rate of 0.9% at December 31, 2020) | Senior Notes
Debt Instrument [Line Items]
Senior notes, face amount	$ 300,000,000
Senior notes, effective interest rate	0.90%
Series CC Notes, interest rate of 3.6%, face amount of $550, maturing April 15, 2024 (effective interest rate of 3.9%)
Debt Instrument [Line Items]
Senior Notes	$ 586,000,000					564,000,000
Series CC Notes, interest rate of 3.6%, face amount of $550, maturing April 15, 2024 (effective interest rate of 3.9%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.60%
Senior notes, face amount	$ 550,000,000
Senior notes, effective interest rate	3.90%
Series DD Notes, interest rate of 2.1%, face amount of $224, maturing October 3, 2022 (effective interest rate of 1.2%)
Debt Instrument [Line Items]
Senior Notes	$ 228,000,000					543,000,000
Series DD Notes, interest rate of 2.1%, face amount of $224, maturing October 3, 2022 (effective interest rate of 1.2%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	2.10%	2.10%
Senior notes, face amount	$ 224,000,000
Senior notes, effective interest rate	1.20%
Series EE Notes, interest rate of 5.8%, face amount of $1,600, maturing May 1, 2025 (effective interest rate of 6.0%)
Debt Instrument [Line Items]
Senior Notes	$ 1,583,000,000					0
Series EE Notes, interest rate of 5.8%, face amount of $1,600, maturing May 1, 2025 (effective interest rate of 6.0%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	5.80%				5.75%
Senior notes, face amount	$ 1,600,000,000				$ 1,600,000,000
Senior notes, effective interest rate	6.00%
Series FF Notes, interest rate of 4.6%, face amount of $1,000, maturing June 15, 2030 (effective interest rate of 4.8%)
Debt Instrument [Line Items]
Senior Notes	$ 986,000,000					0
Series FF Notes, interest rate of 4.6%, face amount of $1,000, maturing June 15, 2030 (effective interest rate of 4.8%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	4.60%			4.625%
Senior notes, face amount	$ 1,000,000,000			$ 1,000,000,000
Senior notes, effective interest rate	4.80%
Series GG Notes, interest rate of 3.5%, face amount of $1,000, maturing October 15, 2032 (effective interest rate of 3.7%)
Debt Instrument [Line Items]
Senior Notes	$ 985,000,000					$ 0
Series GG Notes, interest rate of 3.5%, face amount of $1,000, maturing October 15, 2032 (effective interest rate of 3.7%) | Senior Notes
Debt Instrument [Line Items]
Senior notes, interest rate	3.50%		3.50%
Senior notes, face amount	$ 1,000,000,000		$ 1,000,000,000
Senior notes, effective interest rate	3.70%

LONG-TERM DEBT - Additional Inf

LONG-TERM DEBT - Additional Information (Details)	1 Months Ended					12 Months Ended
	Jan. 31, 2021amendment	Aug. 31, 2020USD ($)	Jul. 31, 2020USD ($)	Jun. 30, 2020USD ($)	Apr. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2020
Debt Instrument [Line Items]
Maximum aggregate borrowings under credit facility (up to)						$ 4,500,000,000
Outstanding borrowings						900,000,000	$ 0
Cash paid for interest, net of amounts capitalized						377,000,000	$ 348,000,000	$ 290,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Borrowings under credit agreement						4,500,000,000
Repayments under credit agreement						3,600,000,000
Outstanding borrowings						900,000,000
Senior Notes
Debt Instrument [Line Items]
Debt retired				$ 853,000,000
Senior Notes | Series EE Notes, interest rate of 5.8%, face amount of $1,600, maturing May 1, 2025 (effective interest rate of 6.0%)
Debt Instrument [Line Items]
Face amount					$ 1,600,000,000	$ 1,600,000,000
Interest rate					5.75%	5.80%
Net proceeds					$ 1,581,000,000
Senior Notes | Series FF Notes, interest rate of 4.6%, face amount of $1,000, maturing June 15, 2030 (effective interest rate of 4.8%)
Debt Instrument [Line Items]
Face amount				$ 1,000,000,000		$ 1,000,000,000
Interest rate				4.625%		4.60%
Net proceeds				$ 985,000,000
Senior Notes | Series Q Notes, interest rate of 2.3%, face amount of $399, maturing January 15, 2022 (effective interest rate of 2.5%)
Debt Instrument [Line Items]
Debt retired				351,000,000
Face amount						$ 399,000,000
Interest rate						2.30%			2.30%
Senior Notes | Series L Notes, interest rate of 3.3%, face amount of $173, maturing September 15, 2022 (effective interest rate of 3.4%)
Debt Instrument [Line Items]
Debt retired				176,000,000
Face amount						$ 173,000,000
Interest rate						3.30%			3.30%
Senior Notes | Series DD Notes, interest rate of 2.1%, face amount of $224, maturing October 3, 2022 (effective interest rate of 1.2%)
Debt Instrument [Line Items]
Debt retired				$ 326,000,000
Face amount						$ 224,000,000
Interest rate						2.10%			2.10%
Senior Notes | Series M Notes, interest rate of 3.4%, face amount of $350, matured October 15, 2020 (effective interest rate of 3.6%)
Debt Instrument [Line Items]
Debt retired			$ 350,000,000
Face amount						$ 350,000,000
Interest rate						3.40%
Senior Notes | Series GG Notes, interest rate of 3.5%, face amount of $1,000, maturing October 15, 2032 (effective interest rate of 3.7%)
Debt Instrument [Line Items]
Face amount		$ 1,000,000,000				$ 1,000,000,000
Interest rate		3.50%				3.50%
Net proceeds		$ 984,000,000
Line of Credit | Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Number of amendments | amendment	2
Line of Credit | Revolving Credit Facility | Subsequent Event | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio	5.50
Line of Credit | Revolving Credit Facility | Subsequent Event | Minimum
Debt Instrument [Line Items]
Maximum leverage ratio	4

LONG-TERM DEBT - Future Princip

LONG-TERM DEBT - Future Principal Payments for Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 1,173
2022	807
2023	682
2024	1,494
2025	2,302
Thereafter	3,918
Long-term debt	$ 10,376	$ 10,940

INTANGIBLE ASSETS AND GOODWIL_2

INTANGIBLE ASSETS AND GOODWILL - Composition of Acquired Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Definite-lived Intangible Assets, gross	$ 3,931	$ 3,560
Accumulated amortization	(937)	(808)
Definite-lived Intangible Assets, net	2,994	2,752
Acquired Indefinite-lived Intangible Assets [Line Items]
Intangible assets	8,989	8,641
Indefinite-lived Intangible Brand Assets
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Brand Assets	5,995	5,889
Costs incurred to obtain contracts with customers
Acquired Finite-Lived Intangible Assets [Line Items]
Definite-lived Intangible Assets, gross	1,674	1,588
Contracts acquired in business combinations and other
Acquired Finite-Lived Intangible Assets [Line Items]
Definite-lived Intangible Assets, gross	$ 2,257	$ 1,972

INTANGIBLE ASSETS AND GOODWIL_3

INTANGIBLE ASSETS AND GOODWILL - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 64
Expected aggregate future amortization expense of intangible assets for 2021	95
Expected aggregate future amortization expense of intangible assets for 2022	95
Expected aggregate future amortization expense of intangible assets for 2023	95
Expected aggregate future amortization expense of intangible assets for 2024	95
Expected aggregate future amortization expense of intangible assets for 2025	$ 95
Minimum
Finite-Lived Intangible Assets [Line Items]
Range of amortization life of intangible assets	15 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Range of amortization life of intangible assets	30 years
Contracts acquired in business combinations and other
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 97	$ 105	$ 111

INTANGIBLE ASSETS AND GOODWIL_4

INTANGIBLE ASSETS AND GOODWILL - Carrying Amount of Goodwill (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 9,048
Foreign currency translation	127
Ending balance	9,175
U.S. & Canada
Goodwill [Roll Forward]
Beginning balance	5,338
Foreign currency translation	9
Ending balance	5,347
Asia Pacific
Goodwill [Roll Forward]
Beginning balance	1,864
Foreign currency translation	71
Ending balance	1,935
EMEA
Goodwill [Roll Forward]
Beginning balance	1,522
Foreign currency translation	57
Ending balance	1,579
CALA
Goodwill [Roll Forward]
Beginning balance	324
Foreign currency translation	(10)
Ending balance	$ 314

PROPERTY AND EQUIPMENT - Compos

PROPERTY AND EQUIPMENT - Composition of our Property and Equipment Balances (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,402	$ 3,205
Accumulated depreciation	(888)	(1,301)
Property and equipment, net	1,514	1,904
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	688	684
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,045	1,100
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	640	1,225
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 29	$ 196

PROPERTY AND EQUIPMENT - Additi

PROPERTY AND EQUIPMENT - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 322	$ 346	$ 256
Property and equipment, net	1,514	1,904
International Operations
Property, Plant and Equipment [Line Items]
Property and equipment, net	679	695
Reimbursed Expenses
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 109	$ 121	$ 147
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	40 years

FAIR VALUE OF FINANCIAL INSTR_3

FAIR VALUE OF FINANCIAL INSTRUMENTS - Carrying Values and Fair Values of Non-Current Financial Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	$ 159	$ 117
Other noncurrent liabilities	(2,366)	(2,236)
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	159	117
Total noncurrent financial assets	159	117
Senior Notes	(8,031)	(6,441)
Commercial paper/Credit Facility	(900)	(3,197)
Other long-term debt	(126)	(174)
Other noncurrent liabilities	(426)	(196)
Total noncurrent financial liabilities	(9,483)	(10,008)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior, mezzanine, and other loans	142	112
Total noncurrent financial assets	142	112
Senior Notes	(8,941)	(6,712)
Commercial paper/Credit Facility	(900)	(3,197)
Other long-term debt	(128)	(179)
Other noncurrent liabilities	(426)	(196)
Total noncurrent financial liabilities	$ (10,395)	$ (10,284)

FAIR VALUE OF FINANCIAL INSTR_4

FAIR VALUE OF FINANCIAL INSTRUMENTS - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commercial paper, maturity term	30 days

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE LOSS - Accumulated Other Comprehensive Income Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance	$ 703	$ 2,225	$ 3,582
Other comprehensive (loss) income before reclassifications	236	37	(387)
Reclassification adjustments	(10)	(7)	17
Total other comprehensive income (loss), net of tax	226	30	$ (370)
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201601Member
Ending balance	430	703	$ 2,225
Intra-entity foreign currency long-term-investment gains (losses)	(44)	6	14
Foreign Currency Translation Adjustments
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance	(368)	(403)	(23)
Other comprehensive (loss) income before reclassifications	229	35	(391)
Reclassification adjustments	0	0	11
Total other comprehensive income (loss), net of tax	229	35	(380)
Ending balance	(139)	(368)	(403)
Derivative Instrument and Other Adjustments
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance	7	12	6
Other comprehensive (loss) income before reclassifications	7	2	4
Reclassification adjustments	(10)	(7)	6
Total other comprehensive income (loss), net of tax	(3)	(5)	10
Ending balance	4	7	12
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance	(361)	(391)	(17)
Total other comprehensive income (loss), net of tax	226	30	(370)
Ending balance	$ (135)	$ (361)	(391)
Accounting Standards Update 2016-01 | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance			0
Accounting Standards Update 2016-01 | Foreign Currency Translation Adjustments | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance			0
Accounting Standards Update 2016-01 | Derivative Instrument and Other Adjustments | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance			(4)
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive Loss | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent [Roll forward] [Abstract]
Beginning balance			$ (4)

BUSINESS SEGMENTS - Segment Rev

BUSINESS SEGMENTS - Segment Revenues (Details) $ in Millions		3 Months Ended									12 Months Ended
		Mar. 31, 2021segment	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of reporting segments | segment											3
Total revenue			$ 2,172	$ 2,254	$ 1,464	$ 4,681	$ 5,371	$ 5,284	$ 5,305	$ 5,012	$ 10,571	$ 20,972	$ 20,758
Forecast
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of reporting segments | segment		2
Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											9,275	19,954	19,276
Total segment | International Operations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											1,910	4,400	4,246
Total segment | U.S. & Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											7,905	16,833	16,289
Total segment | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											612	1,189	1,118
Total segment | EMEA
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											758	1,932	1,869
Unallocated corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											1,296	1,018	1,482
Net fee revenues
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross fee revenues											1,683	3,823	3,638
Contract investment amortization											(132)	(62)	(58)
Total revenue											1,551	3,761	3,580
Net fee revenues | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross fee revenues											1,207	3,160	3,024
Contract investment amortization											(127)	(58)	(54)
Total revenue											1,080	3,102	2,970
Net fee revenues | Total segment | U.S. & Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross fee revenues											914	2,265	2,158
Contract investment amortization											(108)	(48)	(45)
Total revenue											806	2,217	2,113
Net fee revenues | Total segment | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross fee revenues											183	477	479
Contract investment amortization											(7)	(2)	(2)
Total revenue											176	475	477
Net fee revenues | Total segment | EMEA
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross fee revenues											110	418	387
Contract investment amortization											(12)	(8)	(7)
Total revenue											98	410	380
Owned, leased, and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											568	1,612	1,635
Owned, leased, and other | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											440	1,446	1,466
Owned, leased, and other | Total segment | U.S. & Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											198	715	721
Owned, leased, and other | Total segment | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											89	178	182
Owned, leased, and other | Total segment | EMEA
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											153	553	563
Reimbursements
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue	[1]										8,452	15,599	15,543
Reimbursements | Total segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											7,755	15,406	14,840
Reimbursements | Total segment | International Operations
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											1,247	2,394	2,244
Reimbursements | Total segment | U.S. & Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											6,901	13,901	13,455
Reimbursements | Total segment | Asia Pacific
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											347	536	459
Reimbursements | Total segment | EMEA
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenue											$ 507	$ 969	$ 926
[1]	See Note 16 for disclosure of related party amounts.

BUSINESS SEGMENTS - Segment Pro

BUSINESS SEGMENTS - Segment Profits (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits	$ (128)	$ 252	$ (154)	$ 114	$ 274	$ 607	$ 409	$ 510	$ 84	$ 1,800	$ 2,366
Interest expense, net of interest income									(418)	(368)	(318)
Benefit (provision) for income taxes									199	(326)	(438)
NET (LOSS) INCOME	$ (164)	$ 100	$ (234)	$ 31	$ 279	$ 387	$ 232	$ 375	(267)	1,273	1,907
International Operations | Reimbursements
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(62)	(18)	(14)
Total segment | International Operations
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(198)	982	1,155
Total segment | U.S. & Canada
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									198	2,000	1,939
Total segment | U.S. & Canada | Reimbursements
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(80)	(129)	(121)
Total segment | Asia Pacific
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									1	369	456
Total segment | Asia Pacific | Reimbursements
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(18)	(9)	0
Total segment | EMEA
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(200)	318	328
Total segment | EMEA | Reimbursements
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									(33)	(8)	0
Unallocated corporate and other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segments profits									$ (47)	$ (720)	$ (60)

BUSINESS SEGMENTS - Depreciatio

BUSINESS SEGMENTS - Depreciation and Amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	$ 346	$ 341	$ 226
Total segment | U.S. & Canada
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	209	218	97
Total segment | Asia Pacific
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	30	25	26
Total segment | EMEA
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	58	51	51
Unallocated corporate and other
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	$ 49	$ 47	$ 52

BUSINESS SEGMENTS - Capital Exp

BUSINESS SEGMENTS - Capital Expenditures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Capital expenditures	$ 135	$ 653	$ 556
Total segment | U.S. & Canada
Segment Reporting Information [Line Items]
Capital expenditures	12	287	305
Total segment | Asia Pacific
Segment Reporting Information [Line Items]
Capital expenditures	2	2	6
Total segment | EMEA
Segment Reporting Information [Line Items]
Capital expenditures	12	29	36
Unallocated corporate and other
Segment Reporting Information [Line Items]
Capital expenditures	$ 109	$ 335	$ 209

RELATED PARTY TRANSACTIONS - Fi

RELATED PARTY TRANSACTIONS - Financial Data Resulting from Transactions with Related Parties, Income Statement Data (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Total revenue		$ 2,172	$ 2,254	$ 1,464	$ 4,681	$ 5,371	$ 5,284	$ 5,305	$ 5,012	$ 10,571	$ 20,972	$ 20,758
Equity in (losses) earnings	[1]									(141)	13	103
Equity Method Investment
Related Party Transaction [Line Items]
Total revenue										259	815	932
Equity in (losses) earnings										(141)	13	103
Reimbursements
Related Party Transaction [Line Items]
Total revenue	[1]									8,452	15,599	15,543
Reimbursed expenses	[1]									(8,435)	(16,439)	(15,778)
Reimbursements | Equity Method Investment
Related Party Transaction [Line Items]
Total revenue										107	233	332
Reimbursed expenses										$ (110)	$ (236)	$ (337)
[1]	See Note 16 for disclosure of related party amounts.

RELATED PARTY TRANSACTIONS - Ad

RELATED PARTY TRANSACTIONS - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Carrying amount of equity method investments	$ 422	$ 577
Amount by which the fair value of equity method investments exceeds company's share of the book value of the investee's net assets	294	311
Related Party Transaction [Line Items]
Impairment charges	77
JWM Family Enterprise, L.P.
Related Party Transaction [Line Items]
Management fees	$ 3	$ 12	$ 13

RELATED PARTY TRANSACTIONS - Eq

RELATED PARTY TRANSACTIONS - Equity Method Investment Summarized Financial Information, Income Statement (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Revenues	$ 2,172	$ 2,254	$ 1,464	$ 4,681	$ 5,371	$ 5,284	$ 5,305	$ 5,012	$ 10,571	$ 20,972	$ 20,758
Net (loss) income	$ (164)	$ 100	$ (234)	$ 31	$ 279	$ 387	$ 232	$ 375	(267)	1,273	1,907
Equity Method Investment
Related Party Transaction [Line Items]
Revenues									259	815	932
Net (loss) income									$ (212)	$ 80	$ 221

RELATED PARTY TRANSACTIONS - _2

RELATED PARTY TRANSACTIONS - Equity Method Investment Summarized Financial Information, Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Assets (primarily composed of hotel real estate managed by us)	$ 24,701	$ 25,051
Equity Method Investment
Related Party Transaction [Line Items]
Assets (primarily composed of hotel real estate managed by us)	2,348	2,555
Liabilities	$ 1,623	$ 1,691

RELATIONSHIP WITH MAJOR CUSTO_2

RELATIONSHIP WITH MAJOR CUSTOMER - Additional Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020USD ($)property	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)property	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2020USD ($)property	Dec. 31, 2019USD ($)property	Dec. 31, 2018USD ($)
Revenue, Major Customer [Line Items]
Revenues	$ 2,172	$ 2,254	$ 1,464	$ 4,681	$ 5,371	$ 5,284	$ 5,305	$ 5,012	$ 10,571	$ 20,972	$ 20,758
Host Hotels & Resorts Inc
Revenue, Major Customer [Line Items]
Number of properties owned or leased | property	59				60				59	60
Revenues									$ 1,037	$ 2,406	$ 2,542

SUPPLEMENTARY DATA QUARTERLY _3

SUPPLEMENTARY DATA QUARTERLY FINANCIAL DATA - UNAUDITED - Quarterly Financial Data - Unaudited (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 2,172	$ 2,254	$ 1,464	$ 4,681	$ 5,371	$ 5,284	$ 5,305	$ 5,012	$ 10,571	$ 20,972	$ 20,758
Operating income (loss)	(128)	252	(154)	114	274	607	409	510	84	1,800	2,366
Net (loss) income	$ (164)	$ 100	$ (234)	$ 31	$ 279	$ 387	$ 232	$ 375	$ (267)	$ 1,273	$ 1,907
Basic (loss) earnings per share (in USD per share)	$ (0.50)	$ 0.31	$ (0.72)	$ 0.10	$ 0.85	$ 1.17	$ 0.70	$ 1.10	$ (0.82)	$ 3.83	$ 5.45
Diluted (loss) earnings per share (in USD per share)	$ (0.50)	$ 0.31	$ (0.72)	$ 0.09	$ 0.85	$ 1.16	$ 0.69	$ 1.09	$ (0.82)	$ 3.80	$ 5.38