Future Contract Benefits - Summary of Discounted and Undiscounted Expected Future Gross premiums and Expected Future Benefit Payments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Payout Annuities
Undiscounted
Expected future gross premiums	$ 0	$ 0
Expected future benefit payments	3,437	3,460
Discounted
Expected future gross premiums	0	0
Expected future benefit payments	2,034	2,067
Traditional Life
Undiscounted
Expected future gross premiums	13,360	13,257
Expected future benefit payments	14,148	13,919
Discounted
Expected future gross premiums	9,156	9,172
Expected future benefit payments	9,492	9,417
Group Protection
Undiscounted
Expected future benefit payments	7,296	7,086
Discounted
Expected future benefit payments	$ 5,640	$ 5,492

Liability For Future Policy Benefit, Discounted, Befiore Reinsurance

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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

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

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