Interim Financial Statements (Business and Basis of Presentation) (Details)	3 Months Ended
	Mar. 31, 2020 brand store franchises
Product Information [Line Items]
Owned and operated new vehicle franchises | franchises	317
Number of brands | brand	32
Percentage of new vehicle sales from core brands (percent)	89.00%
Dealerships [Member]
Product Information [Line Items]
Number of stores (approximate number for total locations)	231
Collision Centers [Member]
Product Information [Line Items]
Number of stores (approximate number for total locations)	81
AutoNation USA Stores [Member]
Product Information [Line Items]
Number of stores (approximate number for total locations)	5
Automotive Auction Operations [Member]
Product Information [Line Items]
Number of stores (approximate number for total locations)	4
Parts Distribution Centers [Member]
Product Information [Line Items]
Number of stores (approximate number for total locations)	16