v3.26.1
Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses $ 95 $ 50
Less Than Twelve Months, Fair Value 8,541 1,920
More Than Twelve Months, Gross Unrealized Losses 571 560
More Than Twelve Months, Fair Value 3,341 3,472
Total Gross Unrealized Losses 666 610
Total Fair Value 11,882 5,392
CLO    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 4  
Less Than Twelve Months, Fair Value 1,397  
More Than Twelve Months, Gross Unrealized Losses 0  
More Than Twelve Months, Fair Value 0  
Total Gross Unrealized Losses 4  
Total Fair Value 1,397  
Commercial MBS issued by GSEs and GNMA    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 1 0
Less Than Twelve Months, Fair Value 162 0
More Than Twelve Months, Gross Unrealized Losses 8 8
More Than Twelve Months, Fair Value 120 81
Total Gross Unrealized Losses 9 8
Total Fair Value 282 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 76 19
More Than Twelve Months, Gross Unrealized Losses 7 10
More Than Twelve Months, Fair Value 201 226
Total Gross Unrealized Losses 8 11
Total Fair Value 277 245
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 150 148
More Than Twelve Months, Fair Value 857 875
Total Gross Unrealized Losses 150 148
Total Fair Value 857 875
Residential MBS issued by GSEs and GNMA    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 14 0
Less Than Twelve Months, Fair Value 2,084 0
More Than Twelve Months, Gross Unrealized Losses 315 311
More Than Twelve Months, Fair Value 1,408 1,503
Total Gross Unrealized Losses 329 311
Total Fair Value 3,492 1,503
Tax-exempt    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 2 2
Less Than Twelve Months, Fair Value 25 10
More Than Twelve Months, Gross Unrealized Losses 83 75
More Than Twelve Months, Fair Value 701 731
Total Gross Unrealized Losses 85 77
Total Fair Value 726 741
U.S. Treasury securities    
Debt Securities, Available-for-sale [Line Items]    
Less Than Twelve Months, Gross Unrealized Losses 73 47
Less Than Twelve Months, Fair Value 4,797 1,891
More Than Twelve Months, Gross Unrealized Losses 0 0
More Than Twelve Months, Fair Value 0 0
Total Gross Unrealized Losses 73 47
Total Fair Value 4,797 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 8 8
More Than Twelve Months, Fair Value 54 56
Total Gross Unrealized Losses 8 8
Total Fair Value $ 54 $ 56