Reporting Segments (Details) $ in Millions		3 Months Ended
		Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment		2
Net Sales by Reporting Segment
Net sales		$ 2,279.0	$ 2,566.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		271.0	346.0
Merger, acquisition and divestiture expense		21.0	1.0
Restructuring expense		15.0	14.0
Asset impairment cost		9.0	0.0
Other expense (income), net		0.0	14.0
Officer stock awards modification		0.0	2.0
Corporate, including stock-based compensation		37.0	51.0
Equity in affiliates’ earnings, net of tax		(5.0)	(9.0)
Interest income		(2.0)	(3.0)
Interest expense		12.0	14.0
Other postretirement income		(2.0)	0.0
Earnings before income taxes and noncontrolling interest		186.0	262.0
Provision for income taxes		49.0	91.0
Net earnings		137.0	171.0
Net earnings attributable to the noncontrolling interest, net of tax		8.0	11.0
Net earnings attributable to BorgWarner Inc.		129.0	160.0
Segment Reporting Information - Assets
Total assets		9,502.0		$ 9,702.0
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		8,275.0		8,611.0
Engine [Member]
Net Sales by Reporting Segment
Net sales		1,434.0	1,598.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		208.0	241.0
Segment Reporting Information - Assets
Total assets		4,388.0		4,536.0
Drivetrain [Member]
Net Sales by Reporting Segment
Net sales		860.0	982.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		63.0	105.0
Segment Reporting Information - Assets
Total assets		3,887.0		4,075.0
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Net sales		(15.0)	$ (14.0)
Corporate, Non-Segment [Member]
Segment Reporting Information - Assets
Total assets	[1]	$ 1,227.0		$ 1,091.0

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