Leases - Schedule of Future Minimum Rental Payments for Operating Leases (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Future minimum rental commitments on noncancelable leases due in 2020	$ 115	$ 122
Future minimum rental commitments on noncancelable leases due in 2021		103
Future minimum rental commitments on noncancelable leases due in 2022		83
Future minimum rental commitments on noncancelable leases due in 2023		57
Future minimum rental commitments on noncancelable leases due in 2024		56
Future minimum rental commitments on noncancelable leases thereafter		123
Operating Leases, Future Minimum Payments Due		$ 546
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities

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Indicates line item in statement of financial position that includes operating lease liability.

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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