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Basis of Presentation [Abstract]

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Net unrealized gain or loss on foreign-currency transactions of intercompany loan hedges.

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Other related revenue including royalty revenue and customer loyalty revenue.

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The carrying amounts of cash and cash equivalent items related to vehicle programs which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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No definition available.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of cash and cash equivalents, and cash and cash equivalents restricted to withdrawal or usage. Excludes amount for disposal group and discontinued operations. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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No definition available.

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Amount of investment in equity security without readily determinable fair value.

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Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value.

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The difference between the carrying value and the sale price of equity securities, not separately or otherwise categorized as trading or available-for-sale. This element includes investments in which the entity holds a small ownership stake (generally, less than 20% of the shares outstanding) and cannot exert significant influence.

+ References

No definition available.

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This element represents the undistributed income (or loss) of equity method investments, net of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations; such investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

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Amount of investment in equity method investee and investment in and advance to affiliate.

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Amount of lessee's right to use underlying asset under operating lease.

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The cash inflow associated with the sale of equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Amount of cash and cash equivalents restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Basis of Presentation Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Basis of Presentation [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 534	$ 489	$ 534	$ 489	$ 615
Program cash	48	161	48	161	115
Restricted Cash and Cash Equivalents	3	11	3	11
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	585	661	585	661	735	$ 901
Net Unrealized Gain Or Loss Of Foreign Currency Transactions On Intercompany Loan Hedges			3
Proceeds from Sale of Equity Method Investments			64
Gain (Loss) on Sale of Equity Investments			44
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	48		48
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions			4
Equity Securities without Readily Determinable Fair Value, Amount	8		8
Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Cumulative Amount	12		12
Other related Revenue	33		63
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	2,337	2,328	4,257	4,296
Operating Lease, Right-of-Use Asset	2,409		2,409		0
Accounting Standards Update 2016-02 [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					5
Property leases [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Operating Lease, Right-of-Use Asset	2,409		2,409
Property leases [Member] \| Accounting Standards Update 2016-02 [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Operating Lease, Right-of-Use Asset					2,811
Vehicle leases [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Operating Lease, Right-of-Use Asset	216		216
Vehicle leases [Member] \| Accounting Standards Update 2016-02 [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Operating Lease, Right-of-Use Asset					$ 183
Americas [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	1,627	1,590	2,954	2,938
EMEA [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	572	600	1,005	1,047
Asia and Australasia [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	138	138	298	311
Avis [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	1,328	1,351	2,428	2,496
Budget [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	816	777	1,467	1,419
Other Brands [Member]
Adjustments related to New Accounting Pronouncements [Line Items]
Revenues	$ 193	$ 200	$ 362	$ 381