Reporting Segments and Related Information - Adjusted EBIT (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Adjusted EBIT																	$ 1,078.2	$ 995.5		$ 935.5
Loss from disposal activities																		39.7		21.5
Program termination agreement																	11.3
Retirement related obligations																	5.9	17.3
Patent infringement settlement, net of legal costs incurred																				(29.1)
Corporate, including equity in affiliates' earnings and stock-based compensation																	110.0	115.4		107.4
Interest income	(1.5)		(1.3)		(1.0)		(1.0)		(1.0)		(1.0)		(1.3)		(1.4)		(4.8)	(4.7)		(4.8)
Interest expense and finance charges	7.6		8.1		8.8		9.7		6.7		5.0		12.6		15.1		34.2	39.4		74.6
Earnings before income taxes and noncontrolling interest																	869.3	761.0		765.9
Provision for income taxes	44.5		56.3		66.6		50.9		48.4		64.2		68.5		57.5		218.3	238.6		195.3
Net earnings	149.4		172.9		180.1		148.6		126.6		105.9		126.2		163.7		651.0	522.4		570.6
Net earnings attributable to the noncontrolling interest, net of tax	8.0		6.1		6.0		6.6		5.4		4.8		5.6		5.7		26.7	21.5		20.5
Net earnings attributable to BorgWarner Inc.	141.4	[1]	166.8	[1]	174.1	[1]	142.0	[1]	121.2	[1]	101.1	[1]	120.6	[1]	158.0	[1]	624.3	500.9	[1]	550.1
Restructuring expense											27.4						52.3	27.4
Engine [Member]
Segment Reporting Information [Line Items]
Adjusted EBIT																	826.0	786.4		774.3
Drivetrain [Member]
Segment Reporting Information [Line Items]
Adjusted EBIT																	$ 252.2	$ 209.1		$ 161.2

[1] The Company's results were impacted by the following:•Quarter ended December 31, 2013: The Company incurred restructuring expense of $52.3 million, related to the initiation of Drivetrain segment actions designed to improve future profitability and competitiveness. The Company recorded tax benefits of $7.1 million in connection with the restructuring expense. Additionally, the Company recorded a net tax benefit of $4.4 million related to the reversal of certain state deferred tax asset valuation allowances and other tax adjustments.•Quarter ended September 30, 2013: The Company incurred a net tax benefit of $5.6 million, which was comprised of tax benefits of $3.1 million related to 2012 provision to return adjustments and $2.5 million related to the reversal of certain state deferred tax asset valuation allowances.•Quarter ended March 31, 2013: The Company incurred $11.3 million of expense related to a program termination agreement. Retirement related obligations expense of $5.9 million was primarily related to a first quarter 2013 grant of restricted stock awards to certain retiring NEOs as to which the Company waived the forfeiture provisions. The Company recorded tax benefits of $3.8 million and $2.1 million related to the program termination agreement and retirement related obligations. Additionally, the Company recorded a net tax benefit of $1.7 million, which was comprised of a $6.6 million tax benefit related to the extension of the federal research and development credit and other international tax provisions resulting from the retroactive impact of U.S. legislation enacted in January 2013, partially offset by a $4.9 million tax expense related to a comprehensive income adjustment.•Quarter ended December 31, 2012: Retirement related obligations of $17.3 million are comprised of a $5.7 million loss resulting from the settlement of a portion of the Muncie Plant's pension obligation and an $11.6 million expense associated with the retirement of certain NEOs. These obligations were partially offset by a $6.1 million tax benefit. The Company incurred tax expense of $3.9 million which included $11.1 million of U.S. tax expense to correct the income taxes payable balance, partially offset by tax benefits resulting from changes to the statutory income tax rate in certain countries and the settlement of certain tax audits. •Quarter ended September 30, 2012: The Company incurred $1.8 million of expense and $11.2 million of tax expense associated with the completion of the sale of its spark plug business. The Company also recorded restructuring expense of $27.4 million primarily associated with the disposal and future requirements of BERU's on-going business, which was partially offset by a tax benefit of $7.7 million. Additionally, the Company incurred tax expense of $6.9 million primarily resulting from the settlement of certain tax audits.•Quarter ended June 30, 2012: The Company recorded expense of $37.9 million primarily due to the write-down of prior purchase price accounting adjustments included within the disposal group as a result of signing a Master Purchase Agreement to sell the spark plug business to Federal-Mogul Corporation, which was partially offset by a tax benefit of $5.5 million resulting from the write-down. Additionally, the Company recorded tax expense of $9.0 million related to its decision to change its cash repatriation assertion for some of its foreign subsidiaries.