Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($)	3 Months Ended			6 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 2,150,000,000		$ 2,150,000,000
Business divestitures	$ 0		$ 0	(25,000,000)	$ 0
Currency translation and other				(33,000,000)
Goodwill, ending balance	2,018,000,000			$ 2,018,000,000
Goodwill impairment	0
Maximum | Significant Unobservable Inputs (Level 3) | Measurement Input, Cap Rate | Valuation, Income Approach
Goodwill [Roll Forward]
Measurement input, discount rate				17.50%
Minimum | Significant Unobservable Inputs (Level 3) | Measurement Input, Cap Rate | Valuation, Income Approach
Goodwill [Roll Forward]
Measurement input, discount rate				15.00%
Americas
Goodwill [Roll Forward]
Goodwill, beginning balance		638,000,000		$ 638,000,000
Currency translation and other				(9,000,000)
Goodwill, ending balance	608,000,000			608,000,000
EMEA
Goodwill [Roll Forward]
Goodwill, beginning balance		429,000,000		429,000,000
Currency translation and other				(6,000,000)
Goodwill, ending balance	345,000,000			345,000,000
Asia
Goodwill [Roll Forward]
Goodwill, beginning balance		1,083,000,000		1,083,000,000
Currency translation and other				(18,000,000)
Goodwill, ending balance	$ 1,065,000,000			1,065,000,000
RECARO
Goodwill [Roll Forward]
Business divestitures		$ (21,000,000)		(99,000,000)
RECARO | Americas
Goodwill [Roll Forward]
Business divestitures				(21,000,000)
RECARO | EMEA
Goodwill [Roll Forward]
Business divestitures				(78,000,000)
RECARO | Asia
Goodwill [Roll Forward]
Business divestitures				$ 0