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
Dec. 31, 2012
Dec. 31, 2011
Securities (Assets)
    
Fair Value, Less than 12 Months $ 5,255  
Gross Unrealized Losses, Less than 12 Months 20  
Fair Value, 12 Months or Longer 27  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 5,282  
Gross Unrealized Losses, Total 20  
Debt Securities
    
Fair Value, Less than 12 Months 5,247 6,929
Gross Unrealized Losses, Less than 12 Months 13 18
Fair Value, 12 Months or Longer 27 1,492
Gross Unrealized Losses, 12 Months or Longer 0 5
Fair Value, Total 5,274 8,421
Gross Unrealized Losses, Total 13 23
U.S. Government and Agency Securities
    
Fair Value, Less than 12 Months 2,546  
Gross Unrealized Losses, Less than 12 Months 5  
Fair Value, 12 Months or Longer 27  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 2,573  
Gross Unrealized Losses, Total 5  
U.S. Treasury Securities
    
Fair Value, Less than 12 Months 1,012 0
Gross Unrealized Losses, Less than 12 Months 2 0
Fair Value, 12 Months or Longer 0 0
Gross Unrealized Losses, 12 Months or Longer 0 0
Fair Value, Total 1,012 0
Gross Unrealized Losses, Total 2 0
U.S. Agency Securities
    
Fair Value, Less than 12 Months 1,534 6,250
Gross Unrealized Losses, Less than 12 Months 3 15
Fair Value, 12 Months or Longer 27 1,492
Gross Unrealized Losses, 12 Months or Longer 0 5
Fair Value, Total 1,561 7,742
Gross Unrealized Losses, Total 3 20
Corporate and Other Debt
    
Fair Value, Less than 12 Months 2,701 679
Gross Unrealized Losses, Less than 12 Months 8 3
Fair Value, 12 Months or Longer 0 0
Gross Unrealized Losses, 12 Months or Longer 0 0
Fair Value, Total 2,701 679
Gross Unrealized Losses, Total 8 3
Agency
    
Fair Value, Less than 12 Months 1,057  
Gross Unrealized Losses, Less than 12 Months 4  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 1,057  
Gross Unrealized Losses, Total 4  
Auto Loan Asset-backed Securities
    
Fair Value, Less than 12 Months 710  
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 710  
Gross Unrealized Losses, Total 1  
Corporate Bonds
    
Fair Value, Less than 12 Months 934  
Gross Unrealized Losses, Less than 12 Months 3  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 934  
Gross Unrealized Losses, Total 3  
Equity Securities
    
Fair Value, Less than 12 Months 8  
Gross Unrealized Losses, Less than 12 Months 7  
Fair Value, 12 Months or Longer 0  
Gross Unrealized Losses, 12 Months or Longer 0  
Fair Value, Total 8  
Gross Unrealized Losses, Total $ 7