v2.4.0.6
Fair Value Measurements (Rollforward For Assets And Liabilities Measured At Fair Value On A Recurring Basis With Level 3 Significant Unobservable Inputs) (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net $ 18      
Included in Earnings, Liabilities, Net 70 [1]      
Included in Other Comprehensive Income (Loss), Liabilities Net -      
Sales, Liabilities         
Issuances, Liabilities         
Settlements, Liabilities, Net (58)      
Transfers into Level 3, Liabilities         
Transfers out of Level 3, Liabilities         
Ending balance, Liabilities, Net 30   30  
Net change in unrealized gains (losses) included in earnings related to assets and liabilities held 30 [1]      
Mortgage Servicing Rights [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 199 282 182 267
Included in Earnings, Assets (34) [1] (33) [1] (31) [1] (34) [1]
Purchases, Asset 14 19 28 35
Issuance, Assets            
Ending balance, Assets, Net 179 268 179 268
Net change in unrealized gains (losses) included in earnings related to assets and liabilities held (26) [1] (28) [1] (17) [1] (23) [1]
Trading Account Liabilities [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net 52 [2] 25 [2] 7 [2] 10 [2]
Disposition of Morgan Keegan (52) [2]   (52) [2]  
Included in Other Comprehensive Income (Loss), Liabilities Net - [2] - [2] - [2] - [2]
Purchases, Liabilities   (18) [2] 49 [2] (27) [2]
Sales, Liabilities    [2]    [2]    [2]    [2]
Issuances, Liabilities    [2]    [2]    [2]    [2]
Settlements, Liabilities, Net   14 [2] (4) [2] 38 [2]
Transfers into Level 3, Liabilities    [2]    [2]    [2]    [2]
Transfers out of Level 3, Liabilities    [2]    [2]    [2]    [2]
Ending balance, Liabilities, Net   21 [2]   21 [2]
Trading Account Liabilities [Member] | Commercial Agency [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net 42 13 [3] 5 [3] 6 [3]
Disposition of Morgan Keegan (42)   (42) [3]  
Included in Other Comprehensive Income (Loss), Liabilities Net - - [3] - [3] - [3]
Purchases, Liabilities     37 [3]  
Sales, Liabilities       [3]    [3]    [3]
Issuances, Liabilities       [3]    [3]    [3]
Settlements, Liabilities, Net   3 [3]   10 [3]
Transfers into Level 3, Liabilities       [3]    [3]    [3]
Transfers out of Level 3, Liabilities       [3]    [3]    [3]
Ending balance, Liabilities, Net   16 [3]   16 [3]
Trading Account Liabilities [Member] | Other Securities [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net 10 12 [3] 2 [3] 4 [3]
Disposition of Morgan Keegan (10)   (10) [3]  
Included in Other Comprehensive Income (Loss), Liabilities Net - - [3] - [3] - [3]
Purchases, Liabilities   (18) [3] 12 [3] (27) [3]
Sales, Liabilities       [3]    [3]    [3]
Issuances, Liabilities       [3]    [3]    [3]
Settlements, Liabilities, Net   11 [3] (4) [3] 28 [3]
Transfers into Level 3, Liabilities       [3]    [3]    [3]
Transfers out of Level 3, Liabilities       [3]    [3]    [3]
Ending balance, Liabilities, Net   5 [3]   5 [3]
Derivatives, Net [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net   8 13 8
Included in Earnings, Liabilities, Net   25 111 [1] 40 [1]
Included in Other Comprehensive Income (Loss), Liabilities Net   - - -
Sales, Liabilities           
Issuances, Liabilities           
Settlements, Liabilities, Net   (24) (94) (39)
Transfers into Level 3, Liabilities           
Transfers out of Level 3, Liabilities           
Ending balance, Liabilities, Net 30 9 30 9
Net change in unrealized gains (losses) included in earnings related to assets and liabilities held   5 48 [1] 5 [1]
Derivatives, Net [Member] | Interest Rate Options [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net 18 5 13 3
Included in Earnings, Liabilities, Net 70 25 [1] 111 40
Included in Other Comprehensive Income (Loss), Liabilities Net - - - -
Sales, Liabilities            
Issuances, Liabilities            
Settlements, Liabilities, Net (58) (25) (94) (38)
Transfers into Level 3, Liabilities            
Transfers out of Level 3, Liabilities            
Ending balance, Liabilities, Net 30 5 30 5
Net change in unrealized gains (losses) included in earnings related to assets and liabilities held 30 [1] 5 [1] 48 [1] 5 [1]
Derivatives, Net [Member] | Interest Rate Futures And Forward Commitments [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Liabilities, Net   3   5
Included in Other Comprehensive Income (Loss), Liabilities Net   -   -
Sales, Liabilities          
Issuances, Liabilities          
Settlements, Liabilities, Net   1   (1)
Transfers into Level 3, Liabilities          
Transfers out of Level 3, Liabilities          
Ending balance, Liabilities, Net   4   4
Trading Account Assets [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 241 [2] 252 [2] 191 [2] 229 [2]
Disposition of Morgan Keegan (241) [2]   (241) [2]  
Included in Earnings, Assets   11 [2],[4] 3 [2],[4] 16 [2],[4]
Purchases, Asset   2,563 [2] 2,620 [2] 4,763 [2]
Issuance, Assets    [2]    [2]    [2]    [2]
Settlements, Assets   (2,612) [2] (2,573) [2] (4,795) [2]
Transfers into Level 3, Assets       1 [2]
Ending balance, Assets, Net   214 [2]   214 [2]
Trading Account Assets [Member] | Commercial Agency [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 104 84 [3] 51 [3] 54 [3]
Disposition of Morgan Keegan (104)   (104) [3]  
Included in Earnings, Assets   2 [3] 2 [3] 3 [3]
Purchases, Asset   312 [3] 368 [3] 477 [3]
Issuance, Assets       [3]    [3]    [3]
Settlements, Assets   (337) [3] (317) [3] (474) [3]
Transfers into Level 3, Assets       1 [3]
Ending balance, Assets, Net   61 [3]   61 [3]
Trading Account Assets [Member] | Other Securities [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 13 6 [3] 1 [3] 10 [3]
Disposition of Morgan Keegan (13)   (13) [3]  
Included in Earnings, Assets   6 [3] 4 [3] 11 [3]
Purchases, Asset   2,249 [3] 2,248 [3] 4,278 [3]
Issuance, Assets       [3]    [3]    [3]
Settlements, Assets   (2,256) [3] (2,240) [3] (4,294) [3]
Ending balance, Assets, Net   5 [3]   5 [3]
Trading Account Assets [Member] | Obligations Of States And Political Subdivisions [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 124 162 [3] 139 [3] 165 [3]
Disposition of Morgan Keegan (124)   (124) [3]  
Included in Earnings, Assets   3 [3] (3) [3] 2 [3]
Purchases, Asset   2 [3] 4 [3] 8 [3]
Issuance, Assets       [3]    [3]    [3]
Settlements, Assets   (19) [3] (16) [3] (27) [3]
Ending balance, Assets, Net   148 [3]   148 [3]
Securities Available For Sale [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 34 37 36 39
Included in Earnings, Assets   1   1
Included in Other Comprehensive Income (Loss), Assets   (1) (2) (1)
Sales, Assets (16) (2) (16) (2)
Issuance, Assets            
Settlements, Assets (1) (1) (4) (3)
Transfers into Level 3, Assets     3  
Transfers out of Level 3, Assets (1)   (1)  
Ending balance, Assets, Net 16 34 16 34
Securities Available For Sale [Member] | Other Securities [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 3      
Issuance, Assets          
Transfers into Level 3, Assets     3  
Transfers out of Level 3, Assets (1)   (1)  
Ending balance, Assets, Net 2   2  
Securities Available For Sale [Member] | Obligations Of States And Political Subdivisions [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 16 17 20 17
Included in Other Comprehensive Income (Loss), Assets     (2)  
Sales, Assets (16)   (16)  
Issuance, Assets            
Settlements, Assets     (2)  
Ending balance, Assets, Net   17   17
Securities Available For Sale [Member] | Residential Non-Agency [Member]
        
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]        
Beginning balance, Assets, Net 15 20 16 22
Included in Earnings, Assets   1   1
Included in Other Comprehensive Income (Loss), Assets   (1)   (1)
Sales, Assets   (2)   (2)
Issuance, Assets            
Settlements, Assets (1) (1) (2) (3)
Ending balance, Assets, Net $ 14 $ 17 $ 14 $ 17
[1] Included in mortgage income.
[2] All amounts related to trading account assets and trading account liabilities are related to Morgan Keegan (see Note 2 for discussion of sale of Morgan Keegan).
[3] Income from trading account assets primarily represents gains/(losses) on disposition, which inherently includes commissions on security transactions during the period.
[4] Included in discontinued operations, on a net basis.