Reporting Segments (Details) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) segment	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Net Sales by Reporting Segment
Sales Revenue, Goods, Net		$ 2,416.2		$ 2,214.2	$ 7,212.9	$ 6,812.0
Number of reportable segments | segment					2
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		350.0		310.9	$ 1,055.7	967.3
Restructuring expense		13.3		1.3	13.3	26.9
Merger and acquisition expense		6.4		5.9	6.4	18.9
Lease termination settlement		0.0	$ 5.3	0.0	5.3	0.0
Other expense, net		2.7		0.0	2.7	0.0
Asset impairment expense		0.0		106.5	0.0	106.5
Contract expiration gain		0.0		1.3	0.0	(6.2)
Corporate, including equity in affiliates' earnings and stock-based compensation		37.3		33.2	121.4	105.7
Interest income		(1.3)		(1.6)	(4.2)	(4.7)
Interest expense and finance charges		17.6		22.4	53.6	65.1
Earnings before income taxes and noncontrolling interest		274.0		141.9	857.2	655.1
Provision for income taxes		79.4		48.8	241.9	213.4
Net earnings		194.6		93.1	615.3	441.7
Net earnings attributable to the noncontrolling interest, net of tax		9.7		9.8	29.2	29.9
Net earnings attributable to BorgWarner Inc.		184.9		83.3	586.1	411.8
Segment Reporting Information - Assets
Total assets		9,816.2			9,816.2		$ 8,834.7
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		8,355.8			8,355.8		7,347.0
Engine [Member]
Net Sales by Reporting Segment
Sales Revenue, Goods, Net		1,506.4		1,359.3	4,483.6	4,202.7
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		238.5		221.5	729.8	696.3
Segment Reporting Information - Assets
Total assets		4,607.0			4,607.0		4,134.6
Drivetrain [Member]
Net Sales by Reporting Segment
Sales Revenue, Goods, Net		921.8		865.9	2,767.7	2,640.5
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		111.5		89.4	325.9	271.0
Segment Reporting Information - Assets
Total assets		3,748.8			3,748.8		3,212.4
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Sales Revenue, Goods, Net		(12.0)		$ (11.0)	(38.4)	$ (31.2)
Corporate, Non-Segment [Member]
Segment Reporting Information - Assets
Total assets	[1]	$ 1,460.4			$ 1,460.4		$ 1,487.7

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