Leases - Future Minimum Rental Commitments Under Non-Cancelable Operating Leases (Details) $ in Millions	Sep. 30, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Minimum Lease Payments 2020	$ 72
Minimum Lease Payments 2021	64
Minimum Lease Payments 2022	55
Minimum Lease Payments 2023	49
Minimum Lease Payments 2024	45
Minimum Lease Payments Thereafter (to 2033)	191
Total Minimum Lease Payments	476
Sublease Income 2020	(2)
Sublease Income 2021	(1)
Sublease Income 2022	0
Sublease Income 2023	0
Sublease Income 2024	0
Sublease Income Thereafter (to 2033)	0
Total Sublease Income	(3)
Net Lease Commitments 2020	70
Net Lease Commitments 2021	63
Net Lease Commitments 2022	55
Net Lease Commitments 2023	49
Net Lease Commitments 2024	45
Net Lease Commitments Thereafter (to 2033)	191
Total Net Lease Commitments	$ 473

Operating Leases, Future Minimum Payments And Minimum Sublease Income, Net, Due

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