v2.4.0.6
Parent-Only Financial Statements, Statement of Cash Flows (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Cash flows from operating activities:      
Net cash provided by operating activities $ 58,540 $ 13,665 $ 18,772
Securities available for sale:      
Sales proceeds 5,210 23,062 8,668
Prepayments and maturities 59,712 52,618 47,919
Purchases (64,756) (121,235) (53,466)
Loans:      
Other, net (1,509) (157) 2,800
Net cash provided by investing activities (139,890) (35,044) (3,675)
Cash flows from financing activities:      
Net increase (decrease) in short-term borrowings and indebtedness to subsidiaries 7,699 (6,231) 11,308
Long-term debt:      
Proceeds from issuance 27,695 11,687 3,489
Repayment (28,093) (50,555) (63,317)
Preferred stock:      
Cash dividends paid (892) (844) (737)
Proceeds from issuance 1,377 2,501 0
Common stock warrants repurchased (1) (2) (545)
Common stock:      
Proceeds from issuance 2,091 1,296 1,375
Repurchased (3,918) (2,416) (91)
Cash dividends paid (4,565) (2,537) (1,045)
Excess tax benefits related to stock option payments 226 79 98
Net cash used by financing activities 83,770 24,775 (26,133)
Net change in cash and due from banks 2,420 3,396 (11,036)
Cash and due from banks at beginning of year 19,440 16,044 27,080
Cash and due from banks at end of year 21,860 19,440 16,044
Parent Company [Member]
      
Cash flows from operating activities:      
Net cash provided by operating activities 13,365 15,049 14,180
Securities available for sale:      
Sales proceeds 6,171 11,459 2,441
Prepayments and maturities 30 0 0
Purchases (5,845) (16,487) (119)
Loans:      
Net repayments from (advances to) subsidiaries 9,191 1,318 (5,485)
Capital notes and term loans made to subsidiaries (1,850) (1,340) 0
Principal collected on notes/loans made to subsidiaries 2,462 5,779 11,282
Net decrease (increase) in investment in subsidiaries (5,218) (610) 1,198
Other, net (2) 230 15
Net cash provided by investing activities 4,939 349 9,332
Cash flows from financing activities:      
Net increase (decrease) in short-term borrowings and indebtedness to subsidiaries 5,456 (242) 1,860
Long-term debt:      
Proceeds from issuance 16,989 7,058 1,789
Repayment (18,693) (31,198) (23,281)
Preferred stock:      
Cash dividends paid (892) (844) (737)
Proceeds from issuance 1,377 2,501 0
Common stock warrants repurchased (1) (2) (545)
Common stock:      
Proceeds from issuance 2,091 1,296 1,375
Repurchased (3,918) (2,416) (91)
Cash dividends paid (4,565) (2,537) (1,045)
Excess tax benefits related to stock option payments 226 79 98
Other, net (14) 0 0
Net cash used by financing activities (1,944) (26,305) (20,577)
Net change in cash and due from banks 16,360 (10,907) 2,935
Cash and due from banks at beginning of year 19,342 30,249 27,314
Cash and due from banks at end of year $ 35,702 $ 19,342 $ 30,249