Significant Accounting Policies - Additional Information (Details) $ in Millions		3 Months Ended	6 Months Ended
	Oct. 01, 2019 USD ($)	Mar. 31, 2020 USD ($) ReportableSegment	Mar. 31, 2020 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | ReportableSegment		5
Operating lease liabilities	$ 174	$ 154	$ 154
Operating lease right of use asset	174	$ 144	$ 144
Lessee, Operating Lease, Existence of Option to Extend			true
Lessee, Operating Lease, Existence of Option to Terminate			true
Operating lease description			Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised.
Accounting Standards Update 2018-02 [Member] | Retained earnings [Member]
Significant Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle effect of adoption quantification amount	$ 3