Parent Company Financial Statements (Parent Company Statement Of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net cash (used in) provided by operating activities	$ 3,374	$ 823	$ (4,231)
Net (increase) decrease in interest-bearing deposits with banking subsidiary	(36,652)	4,398	29,222
Proceeds from sales and maturities of available-for-sale securities	44,810	34,250	43,995
Net decrease in securities related to AMLF			6,111
Business acquisitions	(214)	(2,332)
Net cash (used in) provided by investing activities	(53,895)	3,192	31,632
Net decrease in short-term borrowings related to AMLF			(6,042)
Proceeds from issuance of long-term debt, net of issuance costs	1,986		4,435
Payments for long-term debt	(2,486)	(341)	(29)
Proceeds from issuance of preferred stock	500
Proceeds from public offering of common stock, net of issuance costs			2,231
Repurchase of TARP common stock warrant			(60)
Purchases of common stock	(675)
Proceeds from exercises of common stock options	40	10	34
Repurchases of common stock for employee tax withholding	(63)	(44)	(38)
Proceeds from issuances of treasury stock for common stock awards and option exercises	9
Payments for cash dividends	(295)	(20)	(168)
Net cash (used in) provided by financing activities	49,403	(3,345)	(27,941)
Net increase (decrease)	(1,118)	670	(540)
Cash and due from banks at beginning of year	3,311	2,641	3,181
Cash and due from banks at end of year	2,193	3,311	2,641
Parent Company [Member]
Net cash (used in) provided by operating activities	(571)	1,453	(24)
Net (increase) decrease in interest-bearing deposits with banking subsidiary	144	(831)	(1,457)
Proceeds from sales and maturities of available-for-sale securities		1	36
Net decrease in securities related to AMLF			3,104
Investments in non-banking subsidiaries and unconsolidated entities	(648)	(277)	(776)
Sale of investment in non-banking subsidiaries and unconsolidated entities	39	127
Business acquisitions	(51)	(141)
Net cash (used in) provided by investing activities	(516)	(1,121)	907
Net decrease in short-term borrowings related to AMLF			(3,063)
Net (decrease) increase in commercial paper	(415)	22	189
Proceeds from issuance of long-term debt, net of issuance costs	1,986		1,992
Payments for long-term debt		(300)
Proceeds from issuance of preferred stock	500
Redemption of TARP preferred stock			(2,000)
Proceeds from public offering of common stock, net of issuance costs			2,231
Repurchase of TARP common stock warrant			(60)
Purchases of common stock	(675)
Proceeds from exercises of common stock options	40	10	34
Repurchases of common stock for employee tax withholding	(63)	(44)	(38)
Proceeds from issuances of treasury stock for common stock awards and option exercises	9
Payments for cash dividends	(295)	(20)	(168)
Net cash (used in) provided by financing activities	1,087	(332)	(883)
Net increase (decrease)
Cash and due from banks at beginning of year
Cash and due from banks at end of year