Future Contract Benefits - Summary of Discounted and Undiscounted Expected Future Gross premiums and Expected Future Benefit Payments (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Payout Annuities
Undiscounted
Expected future gross premiums	$ 0	$ 0
Expected future benefit payments	3,436	3,552
Discounted
Expected future gross premiums	0	0
Expected future benefit payments	2,118	1,943
Traditional Life
Undiscounted
Expected future gross premiums	13,610	13,410
Expected future benefit payments	13,932	14,077
Discounted
Expected future gross premiums	9,559	8,802
Expected future benefit payments	$ 9,734	$ 8,989

Liability For Future Policy Benefit, Discounted, Befiore Reinsurance

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- Definition

Liability for future policy benefit, expected future policy benefit, discounted, before reinsurance.

+ References

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- Definition

Liability For Future Policy Benefit, Undiscounted, Befiore Reinsurance

+ References

No definition available.

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- Definition

Amount, before effect of reinsurance, of discounted balance for expected future gross premium component of liability for future policy benefit.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-6

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- Definition

Amount, before effect of reinsurance, of undiscounted balance for expected future gross premium component of liability for future policy benefit.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 29E
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480046/944-40-55-29E

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480081/944-40-50-6

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- Definition

Amount, before effect of reinsurance, of undiscounted balance for expected future policy benefit and expense component of liability for future policy benefit.

+ References

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