BorgWarner Inc. and Consolidated Subsidiaries Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 2,572.8	$ 2,478.5	$ 2,694.0	$ 2,784.3	$ 2,586.4	$ 2,416.2	$ 2,389.7	$ 2,407.0	$ 10,529.6	$ 9,799.3	$ 9,071.0
Cost of sales	2,030.0	1,962.9	2,114.8	2,192.5	2,021.6	1,894.6	1,876.8	1,890.7	8,300.2	7,683.7	7,142.3
Gross profit	542.8	515.6	579.2	591.8	564.8	521.6	512.9	516.3	2,229.4	2,115.6	1,928.7
Selling, general and administrative expenses	225.8	230.5	236.0	253.4	240.0	225.0	215.1	219.0	945.7	899.1	818.0
Other expense, net	51.4	7.1	30.4	4.9	117.0	22.0	(0.3)	5.8	93.8	144.5	137.5
Operating income	265.6	278.0	312.8	333.5	207.8	274.6	298.1	291.5	1,189.9	1,072.0	973.2
Equity in affiliates’ earnings, net of tax	(10.5)	(15.2)	(13.0)	(10.2)	(12.7)	(14.4)	(14.4)	(9.7)	(48.9)	(51.2)	(42.9)
Interest income	(2.0)	(1.5)	(1.4)	(1.5)	(1.6)	(1.3)	(1.4)	(1.5)	(6.4)	(5.8)	(6.3)
Interest expense and finance charges	13.3	14.4	14.9	16.1	16.9	17.6	18.0	18.0	58.7	70.5	84.6
Other postretirement income	(2.0)	(2.4)	(2.4)	(2.6)	(1.2)	(1.3)	(1.4)	(1.2)	(9.4)	(5.1)	(4.9)
Earnings before income taxes and noncontrolling interest	266.8	282.7	314.7	331.7	206.4	274.0	297.3	285.9	1,195.9	1,063.6	942.7
Provision for income taxes	19.2	66.8	30.4	94.9	338.4	79.4	76.2	86.3	211.3	580.3	306.0
Net earnings	247.6	215.9	284.3	236.8	(132.0)	194.6	221.1	199.6	984.6	483.3	636.7
Net earnings attributable to the noncontrolling interest, net of tax	17.6	12.1	12.5	11.7	14.2	9.7	9.1	10.4	53.9	43.4	41.7
Net earnings attributable to BorgWarner Inc.	$ 230.0	$ 203.8	$ 271.8	$ 225.1	$ (146.2)	$ 184.9	$ 212.0	$ 189.2	$ 930.7	$ 439.9	$ 595.0
Earnings per share — basic	$ 1.11	$ 0.98	$ 1.30	$ 1.07	$ (0.70)	$ 0.88	$ 1.01	$ 0.89	$ 4.47	$ 2.09	$ 2.78
Earnings per share — diluted	$ 1.10	$ 0.98	$ 1.30	$ 1.07	$ (0.70)	$ 0.88	$ 1.00	$ 0.89	$ 4.44	$ 2.08	$ 2.76
Weighted average shares outstanding (thousands):
Basic									208,197	210,429	214,374
Diluted									209,496	211,548	215,328