Debt Under Vehicle Programs and Borrowing Arrangements Debt Under Vehicle Programs and Borrowing Arrangements (Details) $ in Millions	Sep. 30, 2020 USD ($)
Debt Due To Rental Car Funding August 2025 [Member]
Debt Under Vehicle Programs And Borrowing Arrangements [Line Items]
Asset-Backed Securities, at Carrying Value	$ 700
Debt, Weighted Average Interest Rate	2.42%
Debt Due To Rental Car Funding February 2026 [Member]
Debt Under Vehicle Programs And Borrowing Arrangements [Line Items]
Asset-Backed Securities, at Carrying Value	$ 650
Debt, Weighted Average Interest Rate	2.28%

Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are 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. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

No definition available.

Name:	us-gaap_AssetBackedSecuritiesAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant