Reporting Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	$ 1,851.1		$ 1,912.5
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	258.3		271.0
Program termination agreement	11.3		0
Retirement related obligations	5.9		0
Corporate, including equity in affiliates' earnings and stock-based compensation	32.9		36.1
Interest income	(1.0)		(1.4)
Interest expense and finance charges	9.7		15.1
Earnings before income taxes and noncontrolling interest	199.5		221.2
Provision for income taxes	50.9		57.5
Net earnings	148.6		163.7
Net earnings attributable to the noncontrolling interest, net of tax	6.6		5.7
Net earnings attributable to BorgWarner Inc.	142.0		158.0
Segment Reporting Information - Assets
Total assets	6,528.9			6,400.8
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets	5,138.0			4,951.4
Engine [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	1,257.5		1,308.2
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	202.3		209.8
Segment Reporting Information - Assets
Total assets	3,390.8			3,299.2
Drivetrain [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	601.4		611.4
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	56.0		61.2
Segment Reporting Information - Assets
Total assets	1,747.2			1,652.2
Intersegment Elimination [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	(7.8)		(7.1)
Corporate [Member]
Segment Reporting Information - Assets
Total assets	$ 1,390.9	[1]		$ 1,449.4	[1]

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