XML 61 R53.htm IDEA: XBRL DOCUMENT v2.4.1.9

Inventory and Vehicle Floorplan Payable (Components of Inventory) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory [Line Items]
Inventory	$ 2,899.0us-gaap_InventoryNet	$ 2,827.2us-gaap_InventoryNet
New Vehicle [Member]
Inventory [Line Items]
Inventory	2,294.3us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_NewVehicleMember	2,330.8us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_NewVehicleMember
Used Vehicle [Member]
Inventory [Line Items]
Inventory	437.6us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_UsedVehicleMember	346.5us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_UsedVehicleMember
Parts, Accessories, And Other [Member]
Inventory [Line Items]
Inventory	$ 167.1us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_PartsAccessoriesAndOtherMember	$ 149.9us-gaap_InventoryNet / us-gaap_ProductOrServiceAxis = an_PartsAccessoriesAndOtherMember

X

- Details

Name:	us-gaap_InventoryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6386567&loc=d3e3927-108312



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

+ Details

Name:	us-gaap_InventoryNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_ProductOrServiceAxis=an_NewVehicleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ProductOrServiceAxis=an_PartsAccessoriesAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ProductOrServiceAxis=an_UsedVehicleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: