Long-Duration Insurance Contracts - Discount Rates for LFPB (Details)	Mar. 31, 2025	Mar. 31, 2024
Whole Life | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	4.90%	4.60%
Whole Life | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.80%	4.90%
Current discount rate	5.70%	5.40%
Term Life | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.10%	4.20%
Current discount rate	5.40%	5.20%
Term Life | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.20%	4.20%
Current discount rate	5.40%	5.30%
Experience life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	6.10%	6.10%
Current discount rate	5.50%	5.30%
Limited-Pay Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.00%	4.00%
Current discount rate	5.80%	5.40%
Supplemental health | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	5.50%	5.30%
Supplemental health | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	2.80%	2.70%
Current discount rate	5.70%	5.40%
SPIA (life contingent) | Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	1.70%	1.70%
Current discount rate	5.30%	5.20%
SPIA (life contingent) | Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest accretion rate	4.10%	4.10%
Current discount rate	5.30%	5.20%