REPORTING SEGMENTS AND RELATED INFORMATION - Adjusted EBIT (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Adjusted EBIT			$ 1,833	$ 1,182	$ 1,438
Corporate, including stock-based compensation			302	192	206
Restructuring expense		$ 50	163	203	72
Customer warranty settlement			124	0	0
Merger, acquisition and divestiture expense			50	96	11
Loss on sales of businesses			29	0	7
Asset impairments and lease modifications			17	17	0
Net gain on insurance recovery for property damage			(3)	(9)	0
Intangible asset accelerated amortization			0	38	0
Amortization of inventory fair value adjustment	$ 27		0		0
Gain on derecognition of subsidiary (Note 21)			0	0	(177)
Unfavorable arbitration loss			0	0	14
Officer stock awards modification			0	0	2
Equity in affiliates’ earnings, net of tax			(48)	(18)	(32)
Unrealized loss (gain) on equity securities			362	(382)	0
Interest expense, net			93	61	43
Other postretirement (income) expense			(45)	(7)	27
Earnings before income taxes and noncontrolling interest			789	964	1,265
Provision for income taxes			150	397	468
Net earnings			639	567	797
Net earnings attributable to the noncontrolling interest, net of tax			102	67	51
Net earnings attributable to BorgWarner Inc.			537	500	746
Air Management
Segment Reporting Information [Line Items]
Adjusted EBIT			1,070	762	995
e-Propulsion & Drivetrain
Segment Reporting Information [Line Items]
Adjusted EBIT			486	359	443
Loss on sales of businesses			7
Fuel Injection
Segment Reporting Information [Line Items]
Adjusted EBIT			170	39	0
Aftermarket
Segment Reporting Information [Line Items]
Adjusted EBIT			$ 107	$ 22	$ 0