Reporting Segments and Related Information - Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net sales	$ 2,123.1	$ 1,884.0	$ 2,031.9	$ 1,984.2	$ 1,991.9	$ 2,032.1	$ 2,197.0	$ 2,084.1	$ 8,023.2	$ 8,305.1	$ 7,436.6
Cost of sales	1,676.2	1,485.8	1,602.9	1,555.2	1,578.6	1,607.6	1,724.2	1,638.3	6,320.1	6,548.7	5,879.1
Gross profit	446.9	398.2	429.0	429.0	413.3	424.5	472.8	445.8	1,703.1	1,756.4	1,557.5
Selling, general and administrative expenses	178.4	148.0	167.4	168.2	169.4	174.5	181.2	173.8	662.0	698.9	639.7
Other expense, net	68.0	13.1	19.1	1.2	31.7	12.3	11.0	38.8	101.4	93.8	62.6
Operating income	200.5	237.1	242.5	259.6	212.2	237.7	280.6	233.2	939.7	963.7	855.2
Equity in affiliates’ earnings, net of tax	(11.7)	(8.7)	(11.1)	(8.5)	(11.5)	(14.8)	(12.2)	(8.8)	(40.0)	(47.3)	(43.5)
Interest income	(2.2)	(2.0)	(1.6)	(1.7)	(1.2)	(1.4)	(1.4)	(1.5)	(7.5)	(5.5)	(4.8)
Interest expense and finance charges	17.8	15.0	17.6	10.0	10.2	9.0	9.0	8.2	60.4	36.4	34.2
Earnings before income taxes and noncontrolling interest	196.6	232.8	237.6	259.8	214.7	244.9	285.2	235.3	926.8	980.1	869.3
Provision for income taxes	61.2	66.9	80.2	72.1	67.3	71.9	85.3	68.1	280.4	292.6	218.3
Net earnings	135.4	165.9	157.4	187.7	147.4	173.0	199.9	167.2	646.4	687.5	651.0
Net earnings attributable to the noncontrolling interest, net of tax	10.1	8.5	9.3	8.8	7.5	6.4	9.7	8.1	36.7	31.7	26.7
Net earnings attributable to BorgWarner Inc.	$ 125.3	$ 157.4	$ 148.1	$ 178.9	$ 139.9	$ 166.6	$ 190.2	$ 159.1	$ 609.7	$ 655.8	$ 624.3
Earnings per share — basic	$ 0.57	$ 0.70	$ 0.66	$ 0.79	$ 0.62	$ 0.73	$ 0.84	$ 0.70	$ 2.72	$ 2.89	$ 2.73
Earnings per share — diluted	$ 0.56	$ 0.70	$ 0.65	$ 0.79	$ 0.61	$ 0.73	$ 0.83	$ 0.69	$ 2.70	$ 2.86	$ 2.70
Pension settlement									$ 25.7	$ 3.1	$ 0.0
Merger and acquisition expense	$ 17.9	$ 3.9							21.8	0.0	0.0
Tax expense global realignment plan		4.5	$ 10.3
Restructuring expense	24.4	6.3	10.5	$ 9.4	$ 17.8	$ 9.6	$ 13.0	$ 38.4	65.7	90.8	39.8
Tax impact of other tax settlements			3.9
Intangible asset impairment									0.0	10.3	12.5
Tax benefit associated with restructuring	0.4	0.7	2.2	1.2	3.4	1.4	1.7	8.8	3.7	15.3	5.1
Tax benefit on intangible asset impairment										0.4	2.0
Other tax benefits	9.0				0.2	0.9				1.1	2.2
Tax impact of other tax adjustments	7.7	0.4	1.3	2.4					9.9		5.2
Tax benefit associated with merger and acquisition expense	$ 3.8
Gain on previously held equity interest									10.8	0.0	0.0
BERU Diesel Start Systems Pvt. Ltd.
Gain on previously held equity interest									10.8	0.0	0.0
Corporate and Other [Member]
Restructuring expense		$ 3.0	$ 9.4	$ 2.7	5.4	3.5	$ 2.0	$ 1.1	12.5	12.0	4.0
U.S. Plans:
Pension settlement					$ 0.4	$ 2.7			$ 25.7	$ 3.1	$ 0.0