Reporting Segments (Details) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		$ 2,214.2	$ 1,884.0	$ 6,812.0	$ 5,900.1
Number of reportable segments | segment				2
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		305.1	282.2	$ 949.9	883.7
Asset impairment expense		106.5	0.0	106.5	0.0
Restructuring expense		1.3	9.3	26.9	41.3
Merger and acquisition expense		5.9	3.9	18.9	3.9
Contract expiration gain		1.3	0.0	(6.2)	0.0
Gain on previously held equity interest		0.0	0.0	0.0	(10.8)
Corporate, including equity in affiliates' earnings and stock-based compensation		27.4	23.2	88.3	81.8
Interest income		(1.6)	(2.0)	(4.7)	(5.3)
Interest expense and finance charges		22.4	15.0	65.1	42.6
Earnings before income taxes and noncontrolling interest		141.9	232.8	655.1	730.2
Provision for income taxes		48.8	66.9	213.4	219.2
Net earnings		93.1	165.9	441.7	511.0
Net earnings attributable to the noncontrolling interest, net of tax		9.8	8.5	29.9	26.6
Net earnings attributable to BorgWarner Inc.		83.3	157.4	411.8	484.4
Segment Reporting Information - Assets
Total assets		9,007.3		9,007.3		$ 8,825.7
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		7,799.9		7,799.9		7,703.1
Engine [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		1,359.3	1,308.9	4,202.7	4,102.8
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		218.2	211.9	686.4	670.3
Segment Reporting Information - Assets
Total assets		4,233.5		4,233.5		4,018.0
Drivetrain [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		865.9	583.7	2,640.5	1,821.8
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		86.9	70.3	263.5	213.4
Segment Reporting Information - Assets
Total assets		3,566.4		3,566.4		3,685.1
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		(11.0)	$ (8.6)	(31.2)	$ (24.5)
Corporate, Non-Segment [Member]
Segment Reporting Information - Assets
Total assets	[1]	$ 1,207.4		$ 1,207.4		$ 1,122.6

[1] Corporate assets include investments and other long-term receivables and deferred income taxes.