Reporting Segments (Details) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				2
Net Sales by Reporting Segment
Net sales		$ 2,551.0	$ 2,694.0	$ 5,117.0	$ 5,478.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		351.0	395.0	697.0	796.0
Restructuring expense		13.0	31.0	27.0	39.0
Merger, acquisition and divestiture expense		5.0	1.0	6.0	3.0
Other expense (income), net		0.0	0.0	14.0	(5.0)
Officer stock awards modification		0.0	(4.0)	2.0	(4.0)
Corporate, including equity in affiliates' earnings and stock-based compensation		39.0	41.0	81.0	94.0
Interest income		(2.0)	(1.0)	(5.0)	(3.0)
Interest expense		14.0	15.0	28.0	31.0
Other postretirement expense (income)		27.0	(2.0)	27.0	(5.0)
Earnings before income taxes and noncontrolling interest		255.0	314.0	517.0	646.0
Provision for income taxes		73.0	30.0	164.0	125.0
Net earnings		182.0	284.0	353.0	521.0
Net earnings attributable to the noncontrolling interest, net of tax		10.0	12.0	21.0	24.0
Net earnings attributable to BorgWarner Inc.		172.0	272.0	332.0	497.0
Segment Reporting Information - Assets
Total assets		10,231.0		10,231.0		$ 10,095.0
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets		8,686.0		8,686.0		8,651.0
Engine [Member]
Net Sales by Reporting Segment
Net sales		1,569.0	1,674.0	3,167.0	3,390.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		249.0	279.0	490.0	559.0
Segment Reporting Information - Assets
Total assets		4,780.0		4,780.0		4,731.0
Drivetrain [Member]
Net Sales by Reporting Segment
Net sales		998.0	1,034.0	1,980.0	2,117.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT		102.0	116.0	207.0	237.0
Restructuring expense			3.0		6.0
Segment Reporting Information - Assets
Total assets		3,906.0		3,906.0		3,920.0
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Net sales		(16.0)	$ (14.0)	(30.0)	$ (29.0)
Corporate, Non-Segment [Member]
Adjusted earnings before interest, income taxes and noncontrolling interest
Restructuring expense				3.0
Segment Reporting Information - Assets
Total assets	[1]	$ 1,545.0		$ 1,545.0		$ 1,444.0

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