Goodwill and Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 587		$ 593
Accumulated Amortization	(192)		(188)
Net	395		405
Amortization of intangibles	9	$ 10
Patented technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	28		27
Accumulated Amortization	(18)		(17)
Net	10		10
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	495		494
Accumulated Amortization	(133)		(129)
Net	362		365
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	46		51
Accumulated Amortization	(31)		(32)
Net	15		19
Miscellaneous
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	18		21
Accumulated Amortization	(10)		(10)
Net	$ 8		$ 11