v3.26.1
Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses $ 138 $ 50
Less Than Twelve Months, Fair Value 11,030 1,920
More Than Twelve Months, Gross Unrealized Losses 548 560
More Than Twelve Months, Fair Value 3,167 3,472
Total Gross Unrealized Losses 686 610
Total Fair Value 14,197 5,392
CLO    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 2  
Less Than Twelve Months, Fair Value 1,144  
More Than Twelve Months, Gross Unrealized Losses 0  
More Than Twelve Months, Fair Value 0  
Total Gross Unrealized Losses 2  
Total Fair Value 1,144  
Commercial MBS issued by GSEs and GNMA    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 2 0
Less Than Twelve Months, Fair Value 203 0
More Than Twelve Months, Gross Unrealized Losses 8 8
More Than Twelve Months, Fair Value 117 81
Total Gross Unrealized Losses 10 8
Total Fair Value 320 81
Corporate debt securities    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 1 1
Less Than Twelve Months, Fair Value 56 19
More Than Twelve Months, Gross Unrealized Losses 6 10
More Than Twelve Months, Fair Value 146 226
Total Gross Unrealized Losses 7 11
Total Fair Value 202 245
Private label residential MBS    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 0 0
Less Than Twelve Months, Fair Value 0 0
More Than Twelve Months, Gross Unrealized Losses 153 148
More Than Twelve Months, Fair Value 834 875
Total Gross Unrealized Losses 153 148
Total Fair Value 834 875
Residential MBS issued by GSEs and GNMA    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 39 0
Less Than Twelve Months, Fair Value 4,098 0
More Than Twelve Months, Gross Unrealized Losses 313 311
More Than Twelve Months, Fair Value 1,327 1,503
Total Gross Unrealized Losses 352 311
Total Fair Value 5,425 1,503
Tax-exempt    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 5 2
Less Than Twelve Months, Fair Value 58 10
More Than Twelve Months, Gross Unrealized Losses 61 75
More Than Twelve Months, Fair Value 693 731
Total Gross Unrealized Losses 66 77
Total Fair Value 751 741
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 89 47
Less Than Twelve Months, Fair Value 5,471 1,891
More Than Twelve Months, Gross Unrealized Losses 0 0
More Than Twelve Months, Fair Value 0 0
Total Gross Unrealized Losses 89 47
Total Fair Value 5,471 1,891
Other    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 0 0
Less Than Twelve Months, Fair Value 0 0
More Than Twelve Months, Gross Unrealized Losses 7 8
More Than Twelve Months, Fair Value 50 56
Total Gross Unrealized Losses 7 8
Total Fair Value $ 50 $ 56