Reporting Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014 segment		Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Number of reportable segments				2
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	$ 2,032.1		$ 1,806.2	$ 6,313.2		$ 5,551.2
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	290.6		261.4	933.6		799.8
Restructuring expense	13.1		0	67.6		0
Program termination agreement	0		0	0		11.3
Retirement related obligations	0		0	0		5.9
Corporate, including equity in affiliates' earnings and stock-based compensation	22.3		25.4	76.0		83.9
Interest income	(1.4)		(1.3)	(4.3)		(3.3)
Interest expense and finance charges	9.0		8.1	26.2		26.6
Earnings before income taxes and noncontrolling interest	244.9		229.2	765.4		675.4
Provision for income taxes	71.9		56.3	225.3		173.8
Net earnings	173.0		172.9	540.1		501.6
Net earnings attributable to the noncontrolling interest, net of tax	6.4		6.1	24.2		18.7
Net earnings attributable to BorgWarner Inc.	166.6		166.8	515.9		482.9
Segment Reporting Information - Assets
Total assets	7,282.3			7,282.3			6,917.0
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets	5,762.2			5,762.2			5,305.7
Engine [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	1,412.4		1,210.3	4,322.0		3,756.1
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	222.6		195.5	696.0		618.1
Segment Reporting Information - Assets
Total assets	3,968.6			3,968.6			3,519.1
Drivetrain [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	627.0		604.0	2,016.4		1,818.9
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	68.0		65.9	237.6		181.7
Segment Reporting Information - Assets
Total assets	1,793.6			1,793.6			1,786.6
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	(7.3)		(8.1)	(25.2)		(23.8)
Corporate Segment [Member]
Segment Reporting Information - Assets
Total assets	$ 1,520.1	[1]		$ 1,520.1	[1]		$ 1,611.3	[1]

[1] Corporate assets include investments and advances and deferred income taxes.