Tangible Asset Impairments and Asset Write-downs (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
Property, Plant and Equipment [Line Items]
Asset impairment charges				$ 31	$ 26
Restructuring Charges | Selling, general and administrative expenses
Property, Plant and Equipment [Line Items]
Asset impairment charges	$ 26
Held-for-sale | Selling, general and administrative expenses | Dollar Thrifty Headquarters
Property, Plant and Equipment [Line Items]
Asset impairment charges			$ 6
Held-for-sale | Other (income) expense
Property, Plant and Equipment [Line Items]
Asset impairment charges		$ 5
Assets deemed to have no future use | Equipment | Customer contracts
Property, Plant and Equipment [Line Items]
Asset impairment charges			11
Assets deemed to have no future use | Direct vehicle and operating | Equipment | Customer contracts
Property, Plant and Equipment [Line Items]
Asset impairment charges			4
Assets deemed to have no future use | Other (income) expense | Equipment | Customer contracts
Property, Plant and Equipment [Line Items]
Asset impairment charges			$ 7