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Debt and Other Financing Activities - Summary of Long-term Debt (Details) - USD ($)
$ in Millions

Mar. 31, 2026

Sep. 30, 2025

Debt Instrument [Line Items]

Carrying value of debt

$ 1,383

$ 1,394

Other

^[1]

(5)

(6)

Long-term debt (less debt issuance costs)

^[2]

1,374

1,384

3.375% Senior Notes, due 2031 [Member]

Debt Instrument [Line Items]

Carrying value of debt

450

450

2.00% Senior Notes Due 2028 [Member]

Debt Instrument [Line Items]

Carrying value of debt

573

586

6.875% Notes due 2043 [Member]

Debt Instrument [Line Items]

Carrying value of debt

282

282

6.50% Junior Subordinated Notes, Due 2029 [Member]

Debt Instrument [Line Items]

Carrying value of debt

$ 74

$ 72

[1]	Other includes $9 million and $10 million of debt issuance costs as of March 31, 2026 and September 30, 2025, respectively.
[2]	The current portion of the long-term debt was zero for both March 31, 2026 and September 30, 2025.

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