Reporting Segments (Details) $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		$ 2,389.7		$ 2,329.2	$ 4,796.7	$ 4,597.8
Number of reportable segments | segment					2
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		353.9		333.4	$ 705.7	656.4
Lease termination settlement		0.0	$ 5.3	0.0	5.3	0.0
Merger and acquisition expense		0.0		7.2	0.0	13.0
Restructuring expense		0.0		19.2	0.0	25.6
Contract expiration gain		0.0		(7.5)	0.0	(7.5)
Corporate, including equity in affiliates' earnings and stock-based compensation		40.0		35.0	84.1	72.5
Interest income		(1.4)		(1.5)	(2.9)	(3.1)
Interest expense and finance charges		18.0		21.4	36.0	42.7
Earnings before income taxes and noncontrolling interest		297.3		259.6	583.2	513.2
Provision for income taxes		76.2		84.2	162.5	164.6
Net earnings		221.1		175.4	420.7	348.6
Net earnings attributable to the noncontrolling interest, net of tax		9.1		11.0	19.5	20.1
Net earnings attributable to BorgWarner Inc.		212.0		164.4	401.2	328.5
Segment Reporting Information - Assets
Total assets		9,288.5			9,288.5		$ 8,834.7
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		7,838.2			7,838.2		7,347.0
Engine [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		1,481.8		1,444.2	2,977.2	2,843.4
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		244.3		238.1	491.3	474.8
Segment Reporting Information - Assets
Total assets		4,429.6			4,429.6		4,134.6
Drivetrain [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		921.0		895.4	1,845.9	1,774.6
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		109.6		95.3	214.4	181.6
Segment Reporting Information - Assets
Total assets		3,408.6			3,408.6		3,212.4
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Goods, Net		(13.1)		$ (10.4)	(26.4)	$ (20.2)
Corporate, Non-Segment [Member]
Segment Reporting Information - Assets
Total assets	[1]	$ 1,450.3			$ 1,450.3		$ 1,487.7

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