v3.26.1
Fair Value Measurements (Information about Valuation Techniques and Significant Unobservable Inputs Used in Valuation of Level Three Assets and Liabilities Measured at Fair Value on Recurring Basis) (Detail)
¥ in Millions
Mar. 31, 2026
JPY (¥)
Mar. 31, 2025
JPY (¥)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale ¥ 78,020 ¥ 97,694
Available-for-sale debt securities 2,526,416 2,607,637
Equity securities [1] 782,413 626,910
Derivative assets 73,633 43,675
Other assets 1,163 2,586
Derivative Liability 66,805 35,543
Policy liabilities and Policy Account Balances 138,027 136,257
Reinsurance recoverables    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets 1,163 2,586
Variable annuity and variable life insurance contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Policy liabilities and Policy Account Balances 138,027 136,257
Japanese prefectural and foreign municipal bond securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 315,766 406,830
Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 957,449 802,545
CMBS and RMBS in the Americas    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 105,432 106,751
Other asset-backed securities and debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 173,884 198,985
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 276,001 217,654
Equity securities 230,596 [2] 162,210 [3]
Derivative assets [4]
Derivative Liability [4]
Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale [5] 78,020 97,694
Available-for-sale debt securities 2,526,416 2,607,637
Derivative assets 73,633 43,675
Other assets 1,163 2,586
Total 3,261,358 3,190,777
Derivative Liability 66,805 35,543
Policy liabilities and Policy Account Balances 138,027 136,257
Accounts Payable 15,683 15,259
Total financial liabilities 271,771 207,554
Fair Value, Measurements, Recurring | Reinsurance recoverables    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets [6] 1,163 2,586
Fair Value, Measurements, Recurring | Variable annuity and variable life insurance contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Policy liabilities and Policy Account Balances [7] 138,027 136,257
Fair Value, Measurements, Recurring | Japanese prefectural and foreign municipal bond securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 315,766 406,830
Fair Value, Measurements, Recurring | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities [8] 957,449 802,545
Fair Value, Measurements, Recurring | Other asset-backed securities and debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 173,884 198,985
Fair Value, Measurements, Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale [5] 35,684 67,794
Available-for-sale debt securities 276,001 217,654
Other assets 1,163 2,586
Total 551,431 459,061
Policy liabilities and Policy Account Balances 138,027 136,257
Accounts Payable 15,683 15,259
Total financial liabilities 154,267 152,168
Fair Value, Measurements, Recurring | Level 3 | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans held for sale 35,684 67,794
Fair Value, Measurements, Recurring | Level 3 | Reinsurance recoverables    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets [6] 1,163 2,586
Fair Value, Measurements, Recurring | Level 3 | Reinsurance recoverables | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Other assets ¥ 1,163 ¥ 2,586
Fair Value, Measurements, Recurring | Level 3 | Reinsurance recoverables | Annuitization Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 1 1
Fair Value, Measurements, Recurring | Level 3 | Variable annuity and variable life insurance contracts    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Policy liabilities and Policy Account Balances [7] ¥ 138,027 ¥ 136,257
Fair Value, Measurements, Recurring | Level 3 | Variable annuity and variable life insurance contracts | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Policy liabilities and Policy Account Balances 138,027 136,257
Fair Value, Measurements, Recurring | Level 3 | Japanese prefectural and foreign municipal bond securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 10,582 10,878
Fair Value, Measurements, Recurring | Level 3 | Japanese prefectural and foreign municipal bond securities | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 6,381 6,319
Fair Value, Measurements, Recurring | Level 3 | Japanese prefectural and foreign municipal bond securities | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 4,201 4,559
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities [8] 118,191 4,252
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 115,931 302
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities ¥ 1,944 ¥ 3,950
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.07 0.015
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities | Equity Volatility [Member] | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.50  
Fair Value, Measurements, Recurring | Level 3 | CMBS and RMBS in the Americas | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities   ¥ 7,082
Fair Value, Measurements, Recurring | Level 3 | Other asset-backed securities and debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities ¥ 147,228 195,442
Fair Value, Measurements, Recurring | Level 3 | Other asset-backed securities and debt securities | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities 42,120 34,670
Fair Value, Measurements, Recurring | Level 3 | Other asset-backed securities and debt securities | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities ¥ 105,108 ¥ 160,772
Fair Value, Measurements, Recurring | Level 3 | Other asset-backed securities and debt securities | Probability of default | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.002 0.002
Fair Value, Measurements, Recurring | Level 3 | Investment funds | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities ¥ 22,000  
Fair Value, Measurements, Recurring | Level 3 | Investment funds | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 203,796  
Fair Value, Measurements, Recurring | Level 3 | Investment funds and other | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities   ¥ 133,585
Fair Value, Measurements, Recurring | Level 3 | Investment funds and other | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities   22,859
Fair Value, Measurements, Recurring | Level 3 | Certain investment funds | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 4,800 5,766
Fair Value, Measurements, Recurring | Level 3 | Contingent Consideration | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Accounts Payable ¥ 14,084 ¥ 15,259
Fair Value, Measurements, Recurring | Level 3 | Contingent Consideration | EV/Terminal EBITDA multiple | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 15 15
Fair Value, Measurements, Recurring | Level 3 | Certain corporate debt securities | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale debt securities ¥ 316  
Fair Value, Measurements, Recurring | Level 3 | Certain corporate debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.024  
Fair Value, Measurements, Recurring | Level 3 | Certain Contingent Consideration | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Accounts Payable ¥ 1,599  
Fair Value, Measurements, Recurring | Level 3 | Certain Contingent Consideration | EBTDA Volatility [Member] | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 0.35  
Fair Value, Measurements, Recurring | Level 3 | Options held/written and other | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets ¥ 7,611 ¥ 8,297
Derivative Liability 557 652
Fair Value, Measurements, Recurring | Level 3 | Options held/written and other | Appraisals/Broker quotes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets ¥ 376 ¥ 520
Fair Value, Measurements, Recurring | Level 3 | Minimum | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Loans held for sale 0.061 0.07
Fair Value, Measurements, Recurring | Level 3 | Minimum | Reinsurance recoverables | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.011 0.005
Fair Value, Measurements, Recurring | Level 3 | Minimum | Reinsurance recoverables | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0 0
Fair Value, Measurements, Recurring | Level 3 | Minimum | Reinsurance recoverables | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.015 0.015
Fair Value, Measurements, Recurring | Level 3 | Minimum | Variable annuity and variable life insurance contracts | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.011 0.005
Fair Value, Measurements, Recurring | Level 3 | Minimum | Variable annuity and variable life insurance contracts | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0 0
Fair Value, Measurements, Recurring | Level 3 | Minimum | Variable annuity and variable life insurance contracts | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.015 0.015
Fair Value, Measurements, Recurring | Level 3 | Minimum | Variable annuity and variable life insurance contracts | Annuitization Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0 0
Fair Value, Measurements, Recurring | Level 3 | Minimum | Japanese prefectural and foreign municipal bond securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.036 0.058
Fair Value, Measurements, Recurring | Level 3 | Minimum | Other asset-backed securities and debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.004 0.004
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 3.4  
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds | EV/Next twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 3.2  
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds and other | WACC | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   0.133
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds and other | EV/Terminal EBITDA multiple | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   4.2
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds and other | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   4.3
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds and other | EV/Forward EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   4.2
Fair Value, Measurements, Recurring | Level 3 | Minimum | Investment funds and other | EV/Precedent transaction last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   4.3
Fair Value, Measurements, Recurring | Level 3 | Minimum | Certain investment funds | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 0.11 0.115
Fair Value, Measurements, Recurring | Level 3 | Minimum | Certain Contingent Consideration | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 0.048  
Fair Value, Measurements, Recurring | Level 3 | Minimum | Options held/written and other | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Derivative assets 0.12 0.12
Significant unobservable inputs, Derivative liabilities 0.12 0.12
Fair Value, Measurements, Recurring | Level 3 | Maximum | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Loans held for sale 0.099 0.121
Fair Value, Measurements, Recurring | Level 3 | Maximum | Reinsurance recoverables | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.035 0.024
Fair Value, Measurements, Recurring | Level 3 | Maximum | Reinsurance recoverables | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 1 1
Fair Value, Measurements, Recurring | Level 3 | Maximum | Reinsurance recoverables | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.14 0.14
Fair Value, Measurements, Recurring | Level 3 | Maximum | Variable annuity and variable life insurance contracts | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.035 0.024
Fair Value, Measurements, Recurring | Level 3 | Maximum | Variable annuity and variable life insurance contracts | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 1 1
Fair Value, Measurements, Recurring | Level 3 | Maximum | Variable annuity and variable life insurance contracts | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.30 0.30
Fair Value, Measurements, Recurring | Level 3 | Maximum | Variable annuity and variable life insurance contracts | Annuitization Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 1 1
Fair Value, Measurements, Recurring | Level 3 | Maximum | Japanese prefectural and foreign municipal bond securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.098 0.098
Fair Value, Measurements, Recurring | Level 3 | Maximum | Other asset-backed securities and debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.512 0.512
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 9  
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds | EV/Next twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 8  
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds and other | WACC | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   0.237
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds and other | EV/Terminal EBITDA multiple | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   12
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds and other | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   9.5
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds and other | EV/Forward EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   9
Fair Value, Measurements, Recurring | Level 3 | Maximum | Investment funds and other | EV/Precedent transaction last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   11.9
Fair Value, Measurements, Recurring | Level 3 | Maximum | Certain investment funds | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 0.115 0.12
Fair Value, Measurements, Recurring | Level 3 | Maximum | Certain Contingent Consideration | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 0.05  
Fair Value, Measurements, Recurring | Level 3 | Maximum | Options held/written and other | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Derivative assets 0.33 0.33
Significant unobservable inputs, Derivative liabilities 0.33 0.33
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Loans held for sale 0.079 0.094
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Reinsurance recoverables | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.02 0.013
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Reinsurance recoverables | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.028 0.029
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Reinsurance recoverables | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 0.045 0.047
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Reinsurance recoverables | Annuitization Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Other assets 1 1
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Variable annuity and variable life insurance contracts | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.02 0.013
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Variable annuity and variable life insurance contracts | Mortality Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.023 0.023
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Variable annuity and variable life insurance contracts | Lapse Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.056 0.057
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Variable annuity and variable life insurance contracts | Annuitization Rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Policy liabilities and Policy Account Balances 0.644 0.671
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Japanese prefectural and foreign municipal bond securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.08 0.08
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Corporate debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.07 0.015
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Corporate debt securities | Equity Volatility [Member] | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.50  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Other asset-backed securities and debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.054 0.055
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Other asset-backed securities and debt securities | Probability of default | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.002 0.002
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 7.7  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds | EV/Next twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 5.1  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds and other | WACC | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   0.168
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds and other | EV/Terminal EBITDA multiple | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   8.8
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds and other | EV/Last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   7.8
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds and other | EV/Forward EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   7.7
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Investment funds and other | EV/Precedent transaction last twelve months EBITDA multiple | Market Multiples    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities   8.7
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Certain investment funds | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Equity securities 0.112 0.117
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Contingent Consideration | EV/Terminal EBITDA multiple | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 15 15
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Certain corporate debt securities | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Available-for-sale debt securities 0.024  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Certain Contingent Consideration | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 0.049  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Certain Contingent Consideration | EBTDA Volatility [Member] | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Accounts Payable 0.35  
Fair Value, Measurements, Recurring | Level 3 | Weighted Average | Options held/written and other | Discount rate | Discounted cash flows    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Significant unobservable inputs, Derivative assets 0.149 0.147
Significant unobservable inputs, Derivative liabilities 0.149 0.147
[1] The amount of assets under management of variable annuity and variable life insurance contracts included in equity securities were ¥132,313 million and ¥137,933 million as of March 31, 2025 and 2026, respectively. The amount of investment funds and others elected the fair value option included in equity securities were ¥24,960 million and ¥24,845 million as of March 31, 2025 and 2026, respectively.
[2] The amount of ¥168,854 million of investment funds measured at net asset value per share is not included.
[3] The amount of ¥118,666 million of investment funds measured at net asset value per share is not included.
[4] It represents the amount after offset under counterparty netting of derivative assets and liabilities. For the information of input level before netting, see Note 2 “Fair Value Measurements.”
[5] A certain subsidiary elected the fair value option on certain loans held for sale. These loans are multi-family and seniors housing loans and are sold to Federal National Mortgage Association (“Fannie Mae”), Federal Home Loan Mortgage Corporation (“Freddie Mac”) and institutional investors. Included in “Other (income) and expense” in the consolidated statements of income were a gain of ¥428 million, a loss of ¥1,052 million and a loss of ¥4,142 million from the change in the fair value of the loans for fiscal 2024, 2025 and 2026, respectively. No gains or losses were recognized in earnings during fiscal 2024, 2025 and 2026 attributable to changes in instrument-specific credit risk. The amounts of aggregate unpaid principal balance and aggregate fair value of the loans held for sale as of March 31, 2025, were ¥98,135 million and ¥97,694 million, respectively, and the amount of the aggregate fair value was less than the amount of aggregate unpaid principal balance by ¥441 million. The amounts of aggregate unpaid principal balance and aggregate fair value of the loans held for sale as of March 31, 2026, were ¥79,364 million and ¥78,020 million, respectively, and the amount of the aggregate fair value was less than the amount of aggregate unpaid principal balance by ¥1,344 million. The amounts of aggregate unpaid principal balance and aggregate fair value of loans that are 90 days or more past due or, in non-accrual status as of March 31, 2025, were ¥17,098 million and ¥16,346 million, respectively, and the amount of the aggregate fair value was less than the amount of aggregate unpaid principal balance by ¥752 million. The amounts of aggregate unpaid principal balance and aggregate fair value of loans that are 90 days or more past due or, in non-accrual status as of March 31, 2026, were ¥9,858 million and ¥8,657 million, respectively, and the amount of the aggregate fair value was less than the amount of aggregate unpaid principal balance by ¥1,201 million.
[6] Certain subsidiaries elected the fair value option for certain reinsurance contracts held. The fair value of the reinsurance contracts elected for the fair value option in other assets were ¥2,586 million and ¥1,163 million as of March 31, 2025 and 2026, respectively. For the effect of changes in the fair value of those reinsurance contracts on earnings for fiscal 2024, 2025 and 2026, see Note 23 “Income and Expenses Relating to Life Insurance Operations.”
[7] Certain subsidiaries elected the fair value option for the entire variable annuity and variable life insurance contracts held. The fair value of the variable annuity and variable life insurance contracts elected for the fair value option in policy liabilities and policy account balances were ¥136,257 million and ¥138,027 million as of March 31, 2025 and 2026, respectively. For the effect of changes in the fair value of the variable annuity and variable life insurance contracts on earnings for fiscal 2024, 2025 and 2026, see Note 23 “Income and Expenses Relating to Life Insurance Operations.”
[8] A certain subsidiary elected the fair value option for investments in foreign corporate debt securities included in available-for-sale debt securities. Included in “Gains on investment securities and dividends” in the consolidated statements of income were a loss of ¥399 million, gains of ¥441 million and ¥362 million from the change in the fair value of those investments for fiscal 2024, 2025 and 2026, respectively. The amounts of aggregate fair value elected the fair value option were ¥10,679 million and ¥11,927 million as of March 31, 2025 and 2026, respectively.