v2.4.0.6
Securities Available for Sale (Schedule of Available for Sale Securities in an Unrealized Loss Position) (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Securities (Assets) [Member]
    
Fair Value, Less than 12 Months $ 2,765  
Gross Unrealized Losses, Less than 12 Months 15  
Fair Value, 12 Months or Longer 525  
Gross Unrealized Losses, 12 Months or Longer 2  
Fair Value, Total 3,290  
Gross Unrealized Losses, Total 17  
Debt Securities
    
Fair Value, Less than 12 Months 2,760 6,929
Gross Unrealized Losses, Less than 12 Months 5 18
Fair Value, 12 Months or Longer 525 1,492
Gross Unrealized Losses, 12 Months or Longer 2 5
Fair Value, Total 3,285 8,421
Gross Unrealized Losses, Total 7 23
U.S. Government and Agency Securities
    
Fair Value, Less than 12 Months 2,238  
Gross Unrealized Losses, Less than 12 Months 4  
Fair Value, 12 Months or Longer 525  
Gross Unrealized Losses, 12 Months or Longer 2  
Fair Value, Total 2,763  
Gross Unrealized Losses, Total 6  
U.S. Treasury Securities
    
Fair Value, Less than 12 Months 0 0
Gross Unrealized Losses, Less than 12 Months 0 0
Fair Value, 12 Months or Longer 0 0
Gross Unrealized Losses, 12 Months or Longer 0 0
Fair Value, Total 0 0
Gross Unrealized Losses, Total 0 0
U.S. Agency Securities
    
Fair Value, Less than 12 Months 2,238 6,250
Gross Unrealized Losses, Less than 12 Months 4 15
Fair Value, 12 Months or Longer 525 1,492
Gross Unrealized Losses, 12 Months or Longer 2 5
Fair Value, Total 2,763 7,742
Gross Unrealized Losses, Total 6 20
Corporate and Other Debt
    
Fair Value, Less than 12 Months 522 679
Gross Unrealized Losses, Less than 12 Months 1 3
Fair Value, 12 Months or Longer 0 0
Gross Unrealized Losses, 12 Months or Longer 0 0
Fair Value, Total 522 679
Gross Unrealized Losses, Total 1 3
Corporate Bonds
    
Fair Value, Less than 12 Months 522  
Gross Unrealized Losses, Less than 12 Months 1  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 522  
Gross Unrealized Losses, Total 1  
FFELP Student Loan Asset-backed Securities
    
Fair Value, Less than 12 Months 0  
Gross Unrealized Losses, Less than 12 Months 0  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 0  
Gross Unrealized Losses, Total 0  
Equity Securities
    
Fair Value, Less than 12 Months 5  
Gross Unrealized Losses, Less than 12 Months 10  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 5  
Gross Unrealized Losses, Total $ 10