v3.26.1
Fair Value Hierarchy - Fair Value of Loans Held for Investment by Level (Detail) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 4,379 $ 4,905
Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 3,788 4,359
Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 591 546
Corporate    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 342 326
Corporate | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Corporate | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 17 36
Corporate | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 325 290
Commercial real estate    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 417 420
Commercial real estate | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Commercial real estate | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 353 356
Commercial real estate | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 64 64
Residential real estate    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 3,066 3,257
Residential real estate | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Residential real estate | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 3,033 3,222
Residential real estate | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 33 35
Other collateralized    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 511 855
Other collateralized | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Other collateralized | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 374 717
Other collateralized | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 137 138
Other    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 43 47
Other | Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 0 0
Other | Level 2    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value 11 28
Other | Level 3    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value $ 32 $ 19