v3.26.1
AFS and HTM Debt Securities, Gross Unrealized Losses and Fair Value (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale $ (1,489) $ (995)
Less than 12 months, Fair value, available-for-sale 73,818 13,305
12 months or more, Gross unrealized losses, available-for-sale (3,030) (2,996)
12 months or more, Fair value, available-for-sale 36,293 50,012
Total, Gross unrealized losses, available-for-sale (4,519) (3,991)
Total Fair value, available for sale 110,111 63,317
Securities of U.S. Treasury and federal agencies [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale (27) 0
Less than 12 months, Fair value, available-for-sale 12,151 0
12 months or more, Gross unrealized losses, available-for-sale (226) (237)
12 months or more, Fair value, available-for-sale 5,346 6,119
Total, Gross unrealized losses, available-for-sale (253) (237)
Total Fair value, available for sale 17,497 6,119
Securities of U.S. states and political subdivisions [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale (16) (5)
Less than 12 months, Fair value, available-for-sale 1,163 222
12 months or more, Gross unrealized losses, available-for-sale (342) (338)
12 months or more, Fair value, available-for-sale 4,743 5,701
Total, Gross unrealized losses, available-for-sale (358) (343)
Total Fair value, available for sale 5,906 5,923
Federal agency mortgage-backed securities [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale (1,437) (988)
Less than 12 months, Fair value, available-for-sale 54,727 11,307
12 months or more, Gross unrealized losses, available-for-sale (2,448) (2,401)
12 months or more, Fair value, available-for-sale 25,637 37,377
Total, Gross unrealized losses, available-for-sale (3,885) (3,389)
Total Fair value, available for sale 80,364 48,684
Non-agency mortgage-backed securities [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale (1) 0
Less than 12 months, Fair value, available-for-sale 734 0
12 months or more, Gross unrealized losses, available-for-sale (11) (18)
12 months or more, Fair value, available-for-sale 550 744
Total, Gross unrealized losses, available-for-sale (12) (18)
Total Fair value, available for sale 1,284 744
Collateralized loan obligations [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale (8) (2)
Less than 12 months, Fair value, available-for-sale 5,043 1,776
12 months or more, Gross unrealized losses, available-for-sale 0 0
12 months or more, Fair value, available-for-sale 0 0
Total, Gross unrealized losses, available-for-sale (8) (2)
Total Fair value, available for sale 5,043 1,776
Other debt securities [Member]    
Available-for-sale debt securities:    
Less than 12 months, Gross unrealized losses, available-for-sale 0 0
Less than 12 months, Fair value, available-for-sale 0 0
12 months or more, Gross unrealized losses, available-for-sale (3) (2)
12 months or more, Fair value, available-for-sale 17 71
Total, Gross unrealized losses, available-for-sale (3) (2)
Total Fair value, available for sale $ 17 $ 71