v2.4.0.6
Fair Value, Transfers Between Fair Value Levels (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Total $ 0
Trading Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Total 0
Available for sale Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Total 0
Mortgages held for sale [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Total 0
Derivatives [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Total 0
Level 1 [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 0
Transfer Out 0
Level 1 [Member] | Trading Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 0
Transfer Out 0
Level 1 [Member] | Available for sale Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 0
Transfer Out 0
Level 1 [Member] | Mortgages held for sale [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 0
Transfer Out 0
Level 1 [Member] | Derivatives [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 0
Transfer Out 0
Level 2 [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 201
Transfer Out (136)
Level 2 [Member] | Trading Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 10
Transfer Out (14)
Level 2 [Member] | Available for sale Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 93
Transfer Out (43)
Level 2 [Member] | Mortgages held for sale [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 86
Transfer Out (87)
Level 2 [Member] | Derivatives [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 12
Transfer Out 8
Level 3 [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 136
Transfer Out (201)
Level 3 [Member] | Trading Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 14
Transfer Out (10)
Level 3 [Member] | Available for sale Securities [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 43
Transfer Out (93)
Level 3 [Member] | Mortgages held for sale [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In 87
Transfer Out (86)
Level 3 [Member] | Derivatives [Member]
  
Fair Value, Assets and Liabilities Measured on Recurring Basis Transfers Between Fair Value Levels [Line Items]  
Transfer In (8)
Transfer Out $ (12)