Future Policy Benefits - Liability For Future Policy Benefit Expected Future Policy Benefit Undiscounted (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted [Abstract]
Expected future benefit payments		$ 2,155
Expected future gross premiums		839
Traditional Life
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted [Abstract]
Expected future benefit payments	$ 2,874	3,073
Expected future gross premiums	1,042	1,142
Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted [Abstract]
Expected future benefit payments	2,013
Expected future gross premiums	751
Immediate Annuities
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted [Abstract]
Expected future benefit payments	3,271	3,402
Expected future gross premiums	0	0
Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted [Abstract]
Expected future benefit payments	1,371	1,452
Expected future gross premiums	0	0
PRT
Liability for Future Policy Benefit, Expected Future Policy Benefit, Undiscounted [Abstract]
Expected future benefit payments	8,344	3,916
Expected future gross premiums	0	0
Liability For Future Policy Benefit, Expected Future Policy Benefit, Discounted [Abstract]
Expected future benefit payments	4,899	2,708
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

No definition available.

+ Details

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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

+ Details

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