Financial Instruments (Schedule of Carrying Amounts and Estimated Fair Values) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 5,465	$ 4,791
Carrying Amount | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term debt and current portion of long-term debt	540	32
Long-term debt	5,465	4,791
Carrying Amount | Interest rate caps | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps and interest rate caps	13	74
Carrying Amount | Vehicle-backed debt due to Avis Budget Rental Car Funding | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vehicle-backed debt	4,043	3,422
Carrying Amount | Avis Budget Rental Car Funding | Vehicle-backed debt due to Avis Budget Rental Car Funding | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vehicle-backed debt	13,837	15,441
Estimated Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term debt and current portion of long-term debt	546	32
Long-term debt	5,517	4,812
Estimated Fair Value | Interest rate caps | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps and interest rate caps	13	74
Estimated Fair Value | Vehicle-backed debt due to Avis Budget Rental Car Funding | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vehicle-backed debt	4,075	3,435
Estimated Fair Value | Avis Budget Rental Car Funding | Vehicle-backed debt due to Avis Budget Rental Car Funding | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vehicle-backed debt	$ 13,981	$ 15,238