Reporting Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014 segment		Jun. 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	$ 2,197.0		$ 1,893.9	$ 4,281.1		$ 3,745.0
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	330.8		280.1	643.0		538.4
Restructuring expense	15.0		0	54.5		0
Program termination agreement				0		11.3
Retirement related obligations				0		5.9
Corporate, including equity in affiliates' earnings and stock-based compensation	23.0		25.6	53.7		58.5
Interest income	(1.4)		(1.0)	(2.9)		(2.0)
Interest expense and finance charges	9.0		8.8	17.2		18.5
Earnings before income taxes and noncontrolling interest	285.2		246.7	520.5		446.2
Provision for income taxes	85.3		66.6	153.4		117.5
Net earnings	199.9		180.1	367.1		328.7
Net earnings attributable to the noncontrolling interest, net of tax	9.7		6.0	17.8		12.6
Net earnings attributable to BorgWarner Inc.	190.2		174.1	349.3		316.1
Segment Reporting Information - Assets
Total assets	7,457.0			7,457.0			6,917.0
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets	5,920.0			5,920.0			5,305.7
Engine [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	1,497.5		1,288.3	2,909.6		2,545.8
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	241.7		220.3	473.4		422.6
Segment Reporting Information - Assets
Total assets	4,091.4			4,091.4			3,519.1
Drivetrain [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	708.7		613.5	1,389.4		1,214.9
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	89.1		59.8	169.6		115.8
Segment Reporting Information - Assets
Total assets	1,828.6			1,828.6			1,786.6
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	(9.2)		(7.9)	(17.9)		(15.7)
Corporate Segment [Member]
Segment Reporting Information - Assets
Total assets	$ 1,537.0	[1]		$ 1,537.0	[1]		$ 1,611.3	[1]

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