Long-Duration Insurance Contracts - Discount Rates for LFPB (Details)	Mar. 31, 2024	Mar. 31, 2023
Whole Life Insurance | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	4.60%	4.70%
Whole Life Insurance | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.90%	4.90%
Current discount rate	5.40%	5.00%
Term Life Insurance | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.20%	4.10%
Current discount rate	5.20%	4.90%
Term Life Insurance | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.20%	4.30%
Current discount rate	5.30%	5.00%
Experience Life Insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	6.10%	6.10%
Current discount rate	5.30%	5.00%
Limited Pay Whole Life Insurance
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.00%	3.90%
Current discount rate	5.40%	5.00%
Supplemental health | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	5.30%	5.00%
Supplemental health | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	2.70%	2.70%
Current discount rate	5.40%	5.20%
Life Contingent SPIA Retirement Insurance | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	5.20%	4.90%
Life Contingent SPIA Retirement Insurance | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.10%	4.10%
Current discount rate	5.20%	5.00%