v2.4.0.6
Securities (Schedule Of Amortized Cost, Gross Unrealized Gains And Losses, And Estimated Fair Value Of Securities Available For Sale And Securities Held To Maturity) (Detail) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale $ 26,597 $ 23,957
Gross Unrealized Gains - Securities available for sale 649 532
Gross Unrealized Losses - Securities available for sale (14) (18)
Estimated Fair Value - Securities available for sale 27,232 24,471
Amortized Cost - Securities held to maturity 13 16
Gross Unrealized Gains - Securities held to maturity 1 1
Gross Unrealized Losses - Securities held to maturity      
Estimated Fair Value - Securities held to maturity 14 17
U.S. Treasury Securities [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 48 95
Gross Unrealized Gains - Securities available for sale 3 3
Estimated Fair Value - Securities available for sale 51 98
Amortized Cost - Securities held to maturity 2 4
Gross Unrealized Gains - Securities held to maturity 1  
Gross Unrealized Losses - Securities held to maturity      
Estimated Fair Value - Securities held to maturity 3 4
Federal Agency Securities [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 232 147
Gross Unrealized Gains - Securities available for sale 3  
Estimated Fair Value - Securities available for sale 235 147
Amortized Cost - Securities held to maturity 3 3
Gross Unrealized Losses - Securities held to maturity      
Estimated Fair Value - Securities held to maturity 3 3
Residential Agency [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 22,923 21,688
Gross Unrealized Gains - Securities available for sale 578 494
Gross Unrealized Losses - Securities available for sale (7) (7)
Estimated Fair Value - Securities available for sale 23,494 22,175
Amortized Cost - Securities held to maturity 8 9
Gross Unrealized Gains - Securities held to maturity   1
Gross Unrealized Losses - Securities held to maturity      
Estimated Fair Value - Securities held to maturity 8 10
Obligations Of States And Political Subdivisions [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 14 24
Gross Unrealized Gains - Securities available for sale   12
Estimated Fair Value - Securities available for sale 14 36
Residential Non-Agency [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 13 15
Gross Unrealized Gains - Securities available for sale 1 1
Estimated Fair Value - Securities available for sale 14 16
Commercial Agency [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 499 318
Gross Unrealized Gains - Securities available for sale 15 8
Estimated Fair Value - Securities available for sale 514 326
Commercial Non-Agency [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 619 314
Gross Unrealized Gains - Securities available for sale 18 7
Estimated Fair Value - Securities available for sale 637 321
Corporate And Other Debt Securities [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 1,527 539
Gross Unrealized Gains - Securities available for sale 29 5
Gross Unrealized Losses - Securities available for sale (5) (7)
Estimated Fair Value - Securities available for sale 1,551 537
Equity Securities [Member]
   
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]    
Amortized Cost - Securities available for sale 722 817
Gross Unrealized Gains - Securities available for sale 2 2
Gross Unrealized Losses - Securities available for sale (2) (4)
Estimated Fair Value - Securities available for sale $ 722 $ 815