Restructuring Activities - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Minimum
Restructuring Cost and Reserve [Line Items]
Expected costs for restructuring activities	$ 3	$ 3
Maximum
Restructuring Cost and Reserve [Line Items]
Expected costs for restructuring activities	5	5
Employee Termination Benefits
Restructuring Cost and Reserve [Line Items]
Expenses recognized during the period	$ 4	$ 10