Shareholders' Equity (Shares Issued And Shares Surrendered To Satisfy Tax Withholdings In Connection With Restricted Stock Units) (Details) - Restricted Stock Units (RSUs) - shares shares in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	0.3	0.5
Shares surrendered to AutoNation to satisfy tax withholding obligations (in shares)	0.1	0.2