v3.26.1
Fair Value Hierarchy - Schedule of Level 3 Assets, and Ranges and Weighted Averages of Significant Unobservable Inputs (Detail)
$ in Millions
Mar. 31, 2026
USD ($)
yr
Dec. 31, 2025
USD ($)
yr
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Total financial assets at fair value | $ $ 1,139,251 $ 963,966
Level 3    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Total financial assets at fair value | $ 20,836 20,324
Level 3 | Loans and securities backed by real estate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Total financial assets at fair value | $ $ 167 $ 155
Level 3 | Loans and securities backed by real estate | Minimum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.033 0.031
Level 3 | Loans and securities backed by real estate | Minimum | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.223 0.223
Level 3 | Loans and securities backed by real estate | Minimum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.4 0.3
Level 3 | Loans and securities backed by real estate | Maximum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.431 0.451
Level 3 | Loans and securities backed by real estate | Maximum | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.930 0.625
Level 3 | Loans and securities backed by real estate | Maximum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 17.5 9.0
Level 3 | Loans and securities backed by real estate | Weighted Average | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.100 0.106
Level 3 | Loans and securities backed by real estate | Weighted Average | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.847 0.365
Level 3 | Loans and securities backed by real estate | Weighted Average | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 3.7 3.4
Level 3 | Corporate debt instruments    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Total financial assets at fair value | $ $ 736 $ 484
Level 3 | Corporate debt instruments | Minimum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.023 0.021
Level 3 | Corporate debt instruments | Minimum | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.041 0.041
Level 3 | Corporate debt instruments | Minimum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 2.5 2.3
Level 3 | Corporate debt instruments | Maximum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.276 0.180
Level 3 | Corporate debt instruments | Maximum | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.692 0.720
Level 3 | Corporate debt instruments | Maximum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 4.6 14.7
Level 3 | Corporate debt instruments | Weighted Average | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.161 0.080
Level 3 | Corporate debt instruments | Weighted Average | Recovery rate    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.388 0.323
Level 3 | Corporate debt instruments | Weighted Average | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 3.1 3.9
Level 3 | Other    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Total financial assets at fair value | $ $ 302 $ 265
Level 3 | Other | Minimum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.098 0.084
Level 3 | Other | Minimum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.2 0.2
Level 3 | Other | Maximum | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.248 0.300
Level 3 | Other | Maximum | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 6.8 8.7
Level 3 | Other | Weighted Average | Yield    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 0.173 0.175
Level 3 | Other | Weighted Average | Duration (years)    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Measurement input 2.7 2.6