v2.4.0.6
Maturities of Securities Available for Sale and Securities Held to Maturity (Detail) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Investment [Line Items]    
Securities available for sale fair value Within 1 year $ 7,011  
Securities available for sale fair value After 1 year through 5 years 9,895  
Securities available for sale fair value After 5 years through 10 years 7,163  
Securities available for sale fair value After 10 years 24,740  
Securities available for sale 48,809 46,123
Securities available for sale Within 1 year amortized cost 6,995  
Securities available for sale After 1 year through 5 years amortized cost 9,828  
Securities available for sale After 5 years through 10 years amortized cost 7,021  
Securities available for sale After 10 years amortized cost 24,485  
Securities available for sale Amortized Cost 48,329 45,644
Securities held to maturity Within 1 year     
Securities held to maturity After 1 year through 5 years 100  
Securities held to maturity After 5 years through 10 years 11,903  
Securities held to maturity After 10 years 11,313  
Securities held to maturity, fair value 23,316 18,732
Securities held to maturity Within 1 year amortized cost     
Securities held to maturity After 1 year through 5 years amortized cost 100  
Securities held to maturity After 5 years through 10 years amortized cost 11,676  
Securities held to maturity After 10 years amortized cost 11,144  
Securities held to maturity 22,920 18,194
U.S. agency mortgage-backed securities
   
Investment [Line Items]    
Securities available for sale fair value After 1 year through 5 years 126 [1]  
Securities available for sale fair value After 5 years through 10 years 3,986 [1]  
Securities available for sale fair value After 10 years 15,707 [1]  
Securities available for sale 19,819 [1] 20,476
Securities available for sale Amortized Cost 19,465 20,080
Securities held to maturity Within 1 year    [1]  
Securities held to maturity After 5 years through 10 years 11,540 [1]  
Securities held to maturity After 10 years 11,055 [1]  
Securities held to maturity, fair value 22,595 [1] 18,289
Securities held to maturity 22,188 17,750
Asset-backed securities
   
Investment [Line Items]    
Securities available for sale fair value Within 1 year 400  
Securities available for sale fair value After 1 year through 5 years 589  
Securities available for sale fair value After 5 years through 10 years 760  
Securities available for sale fair value After 10 years 8,037  
Securities available for sale 9,786 8,164
Securities available for sale Amortized Cost 9,706 8,104
Corporate debt securities
   
Investment [Line Items]    
Securities available for sale fair value Within 1 year 1,879  
Securities available for sale fair value After 1 year through 5 years 5,738  
Securities available for sale 7,617 6,256
Securities available for sale Amortized Cost 7,554 6,197
Certificates of deposit
   
Investment [Line Items]    
Securities available for sale fair value Within 1 year 4,083  
Securities available for sale fair value After 1 year through 5 years 1,817  
Securities available for sale 5,900 6,161
Securities available for sale Amortized Cost 5,890 6,150
U.S. agency notes
   
Investment [Line Items]    
Securities available for sale fair value After 1 year through 5 years 1,625  
Securities available for sale fair value After 5 years through 10 years 2,411  
Securities available for sale 4,036 3,464
Securities available for sale Amortized Cost 4,040 3,465
Non-agency residential mortgage-backed securities
   
Investment [Line Items]    
Securities available for sale fair value After 5 years through 10 years 6  
Securities available for sale fair value After 10 years 703  
Securities available for sale 709 733
Securities available for sale Amortized Cost 747 796
Commercial paper
   
Investment [Line Items]    
Securities available for sale fair value Within 1 year 649  
Securities available for sale 649 574
Securities available for sale Amortized Cost 649 574
Other securities
   
Investment [Line Items]    
Securities available for sale fair value After 10 years 293  
Securities available for sale 293 295
Securities available for sale Amortized Cost 278 278
Securities held to maturity Within 1 year     
Securities held to maturity After 1 year through 5 years 100  
Securities held to maturity After 5 years through 10 years 363  
Securities held to maturity After 10 years 258  
Securities held to maturity, fair value 721 443
Securities held to maturity $ 732 $ 444
[1] Mortgage-backed securities have been allocated to maturity groupings based on final contractual maturities. Actual maturities will differ from final contractual maturities because borrowers on a certain portion of loans underlying these securities have the right to prepay their obligations.