v3.26.1
Fair Value Hierarchy - Summary of Weighted Average of Significant Unobservable Inputs, Loans (Detail)
$ in Millions
Mar. 31, 2026
USD ($)
yr
Dec. 31, 2025
USD ($)
yr
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value $ 4,379 $ 4,905
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 591 546
Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 342 326
Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 325 290
Real estate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 97 99
Other collateralized    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 511 855
Other collateralized | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 137 138
Other    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value 43 47
Other | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Loans at fair value $ 32 $ 19
Minimum | Yield | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.061 0.064
Minimum | Yield | Other collateralized | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.058 0.057
Minimum | Recovery rate | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.321 0.325
Minimum | Recovery rate | Real estate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.690 0.690
Minimum | Duration (years) | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input | yr 2.9 3.1
Maximum | Yield | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.214 0.199
Maximum | Yield | Other collateralized | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.063 0.063
Maximum | Recovery rate | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.949 0.949
Maximum | Recovery rate | Real estate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.992 0.992
Maximum | Duration (years) | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input | yr 4.1 4.4
Weighted Average | Yield | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.113 0.180
Weighted Average | Yield | Other collateralized | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.058 0.057
Weighted Average | Recovery rate | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.616 0.654
Weighted Average | Recovery rate | Real estate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input 0.746 0.761
Weighted Average | Duration (years) | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Measurement input | yr 3.1 3.3