Reporting Segments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012	Dec. 31, 2012
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	$ 1,893.9		$ 1,856.4	$ 3,745.0		$ 3,768.9
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	280.1		265.1	538.4		536.1
Program termination agreement	0		0	11.3		0
Retirement related obligations	0		0	5.9		0
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	0		(37.9)	0		(37.9)
Corporate, including equity in affiliates' earnings and stock-based compensation	25.6		21.2	58.5		57.3
Interest income	(1.0)		(1.3)	(2.0)		(2.7)
Interest expense and finance charges	8.8		12.6	18.5		27.7
Earnings before income taxes and noncontrolling interest	246.7		194.7	446.2		415.9
Provision for income taxes	66.6		68.5	117.5		126.0
Net earnings	180.1		126.2	328.7		289.9
Net earnings attributable to the noncontrolling interest, net of tax	6.0		5.6	12.6		11.3
Net earnings attributable to BorgWarner Inc.	174.1		120.6	316.1		278.6
Segment Reporting Information - Assets
Total assets	6,705.4			6,705.4			6,400.8
Operating Segments [Member]
Segment Reporting Information - Assets
Total assets	5,213.3			5,213.3			4,951.4
Engine [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	1,288.3		1,269.6	2,545.8		2,577.8
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	220.3		210.5	422.6		420.3
Segment Reporting Information - Assets
Total assets	3,451.0			3,451.0			3,299.2
Drivetrain [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	613.5		593.9	1,214.9		1,205.3
Adjusted earnings before interest, income taxes and noncontrolling interest
Adjusted EBIT	59.8		54.6	115.8		115.8
Segment Reporting Information - Assets
Total assets	1,762.3			1,762.3			1,652.2
Intersegment Eliminations [Member]
Net Sales by Reporting Segment
Segment Reporting, Entity Consolidated Revenue	(7.9)		(7.1)	(15.7)		(14.2)
Corporate Segment [Member]
Segment Reporting Information - Assets
Total assets	$ 1,492.1	[1]		$ 1,492.1	[1]		$ 1,449.4	[1]

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