Restatement of Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Asbestos-related adjustments										$ 0.0	$ (48.6)	$ 51.4
Retained earnings		$ 4,531.0				$ 4,215.2				4,531.0	4,215.2	3,733.6	$ 3,273.1
Other expense, net		117.0	$ 22.0	$ (0.3)	$ 5.8	(9.1)	$ 109.9	$ 25.0	$ 11.7	144.5	137.5	152.8
Operating income		209.0	275.9	299.5	292.7	293.0	151.5	269.4	264.2	1,077.1	978.1	888.3
Earnings before income taxes and noncontrolling interest		206.4	274.0	297.3	285.9	286.4	143.1	259.6	253.6	1,063.6	942.7	875.4
Provision for income taxes		338.4	79.4	76.2	86.3	92.4	49.0	84.2	80.4	580.3	306.0	261.5
Net earnings		(132.0)	194.6	221.1	199.6	194.0	94.1	175.4	173.2	483.3	636.7	613.9
Net earnings attributable to the noncontrolling interest, net of tax											41.7	36.7
Net earnings attributable to BorgWarner Inc.		$ (146.2)	$ 184.9	$ 212.0	$ 189.2	$ 182.2	$ 84.3	$ 164.4	$ 164.1	$ 439.9	$ 595.0	$ 577.2
Earnings per share — basic		$ (0.70)	$ 0.88	$ 1.01	$ 0.89	$ 0.86	$ 0.40	$ 0.76	$ 0.75	$ 2.09	$ 2.78	$ 2.57
Earnings per share — diluted		$ (0.70)	$ 0.88	$ 1.00	$ 0.89	$ 0.86	$ 0.39	$ 0.76	$ 0.75	$ 2.08	$ 2.76	$ 2.56
Comprehensive income attributable to BorgWarner Inc.	[1]									$ 672.0	$ 483.1	$ 350.6
Comprehensive income										726.8	519.7	382.2
Asbestos-related adjustments						$ (47.3)	$ (1.2)			0.0	(48.6)	51.4
Deferred income tax provision (benefit)										$ 41.8	6.8	(5.6)
Scenario, Previously Reported [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Asbestos-related adjustments											703.6
Retained earnings												4,210.1	3,717.1
Other expense, net											889.7	101.4
Operating income											225.9	939.7
Earnings before income taxes and noncontrolling interest											190.5	926.8
Provision for income taxes											30.3	280.4
Net earnings											160.2	646.4
Net earnings attributable to the noncontrolling interest, net of tax											41.7	36.7
Net earnings attributable to BorgWarner Inc.											$ 118.5	$ 609.7
Earnings per share — basic											$ 0.55	$ 2.72
Earnings per share — diluted											$ 0.55	$ 2.70
Comprehensive income attributable to BorgWarner Inc.											$ 6.6	$ 383.1
Comprehensive income											43.2	414.7
Asbestos-related adjustments											703.6	0.0
Deferred income tax provision (benefit)											(268.9)	13.3
Restatement Adjustment [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Retained earnings												(476.5)	$ (444.0)	$ 410.1
Reversal of asbestos-related charge											700.6
Reversal of asbestos-related charge, net of tax											438.7
Other expense, net											(752.2)	51.4
Operating income											752.2	(51.4)
Earnings before income taxes and noncontrolling interest											752.2	(51.4)
Provision for income taxes											275.7	(18.9)
Net earnings											476.5	(32.5)
Net earnings attributable to the noncontrolling interest, net of tax											0.0	0.0
Net earnings attributable to BorgWarner Inc.											$ 476.5	$ (32.5)
Earnings per share — basic											$ 2.23	$ (0.15)
Earnings per share — diluted											$ 2.21	$ (0.14)
Comprehensive income attributable to BorgWarner Inc.											$ 476.5	$ (32.5)
Comprehensive income											476.5	(32.5)
Asbestos-related adjustments											(752.2)	51.4
Deferred income tax provision (benefit)											$ 275.7	$ (18.9)

[1] *Net of income taxes.