Other (Income) Expense (Details) (USD $) In Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2008
Other Income and Expenses [Abstract]
Patent infringement settlement	$ (29.1)	$ 0	$ (29.1)	$ 0	$ (4.0)
Environmental litigation settlement	0	28.0	0	28.0
BERU - Eichenauer equity investment gain	0	(8.0)	0	(8.0)
Other	0.2	0.3	(1.4)	1.9
Other (income) expense	(28.9)	20.3	(30.5)	21.9
Patent infringement settlement - Cash received	32.5
Patent infringement settlement - Expense	$ 3.4

Gain Loss On Environmental Settlement.

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Namespace Prefix:	bwa
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)(2)
-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The net proceeds or assets obtained in excess of (less than) the net carrying amount of assets recorded, or assets distributed and liabilities assumed less than (in excess of) estimated litigation liability extinguished, in settlement of a litigation matter. Represents (for other than an insurance entity in its normal claims settlement process), the amount of income (expense) recognized in the period to settle pending or threatened litigation and insurance claims.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the expenses incurred by the entity which are directly related and attributable to receiving an award in settlement of litigation.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the gross amount awarded, to be received by, or to be remitted to the entity in settlement of litigation occurring during the period.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

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Balance Type:	debit
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- Details

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- Definition

The aggregate amount of other nonrecurring expenses, not previously categorized, that are infrequent in occurrence or unusual in nature.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 20
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6365513&loc=d3e15122-107781

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration