Related Party Transactions (Details) (ESL Investments, Inc. [Member])	Dec. 31, 2013
ESL Investments, Inc. [Member]
Related Party Transaction [Line Items]
Majority ownership percentage in which agreements with manufacturers eliminate potential adverse consequences	50.00%

The maximum percentage threshold of shares owned by an investor not subject to voting or other restrictions under the terms of certain letter agreements with certain automotive manufacturers.

No definition available.

Name:	an_RelatedPartyMaximumOwnershipPercentageNotSubjectToVotingRestrictions
Namespace Prefix:	an_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant