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New Accounting Standards (Details) - USD ($) $ in Millions	Mar. 31, 2022	Oct. 01, 2021	Sep. 30, 2021
Liabilities
Long-Term debt	$ 1,025		$ 1,008
Equity
Additional paid-in capital	765		798
Retained earnings	$ 1,068		935
3.25 percent convertible notes due 2037 \| Convertible Notes Payable
Equity
Interest rate	3.25%	3.25%
Cumulative Effect, Period of Adoption, Adjustment
Liabilities
Long-Term debt		$ 1,031
Equity
Additional paid-in capital		758
Retained earnings		$ 952
Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
Liabilities
Long-Term debt			23
Equity
Additional paid-in capital			(40)
Retained earnings			$ 17