Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stockholders' Equity
Beginning balance			$ 4,844
Contributions from noncontrolling interest stockholders	$ 4		0	$ 4
Net earnings attributable to BorgWarner Inc.	111	$ 194	142	526
Net earnings attributable to the noncontrolling interest, net of tax	18	13	40	34
Other comprehensive (loss) income	192	$ 93	182	$ 448
Ending balance	$ 4,918		$ 4,918
Dividends declared (in dollar per share)	$ 0.17	$ 0.17	$ 0.51	$ 0.51
Issued common stock
Increase (Decrease) in Stockholders' Equity
Beginning balance	$ 3	$ 3	$ 3	$ 3
Ending balance	3	3	3	3
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity
Beginning balance	1,115	1,116	1,145	1,146
Net issuance for executive stock plan	5	4	(11)	(5)
Net issuance of restricted stock	8	9	(6)	(12)
Ending balance	1,128	1,129	1,128	1,129
Treasury stock
Increase (Decrease) in Stockholders' Equity
Beginning balance	(1,623)	(1,653)	(1,657)	(1,585)
Net issuance for executive stock plan		1	12	8
Net issuance of restricted stock		(1)	22	24
Purchase of treasury stock				(100)
Ending balance	(1,623)	(1,653)	(1,623)	(1,653)
Retained earnings
Increase (Decrease) in Stockholders' Equity
Beginning balance	5,903	5,598	5,942	5,336
Dividends declared	(35)	(35)	(105)	(105)
Net earnings attributable to BorgWarner Inc.	111	194	142	526
Ending balance	5,979	5,757	5,979	5,757
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity
Beginning balance	(787)	(670)	(727)	(674)
Other comprehensive (loss) income	57	(109)	(3)	(105)
Ending balance	(730)	(779)	(730)	(779)
Noncontrolling interests
Increase (Decrease) in Stockholders' Equity
Beginning balance	152	108	138	119
Dividends declared	(15)	1	(20)	(29)
Net earnings attributable to the noncontrolling interest, net of tax	18	13	40	34
Other comprehensive (loss) income	6	(5)	3	(7)
Ending balance	$ 161	$ 121	$ 161	$ 121