Future Policy Benefits - Schedule of Liability For Future Policy Benefit Expected Future Policy Benefit Undiscounted (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Traditional Life
Undiscounted
Expected future benefit payments	$ 2,569	$ 2,843
Expected future gross premiums	875	978
Discounted
Expected future benefit payments	1,892	2,073
Expected future gross premiums	650	728
Immediate annuities
Undiscounted
Expected future benefit payments	3,125	3,212
Expected future gross premiums	0	0
Discounted
Expected future benefit payments	1,304	1,392
Expected future gross premiums	0	0
PRT
Undiscounted
Expected future benefit payments	11,809	8,449
Expected future gross premiums	0	0
Discounted
Expected future benefit payments	7,363	5,470
Expected future gross premiums	$ 0	$ 0

Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted

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- Definition

Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted, Before Reinsurance

+ References

No definition available.

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- Definition

Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted

+ References

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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.

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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/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

Reference 2: 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

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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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