Fair Value Disclosures (Roll Forward of Level 3 Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Mortgage banking income	$ (182)	$ (83)	$ (398)	$ (178)
Trading [Member]
Beginning balance	1	1	1	11
Interest income	0	0	0	0
Mortgage banking income	0	0	0	0
Other noninterest income	0	0	0	(3)
Included in unrealized net holding gains (losses) in other comprehensive income (loss)	0	0	0	0
Purchases	0	2	0	2
Issuances	0	0	0	0
Sales	0	(9)	0	(9)
Settlements	0	7	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	1	1	1	1
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period	0	0	0	0
States and Political Subdivisions [Member]
Beginning balance		52		119
Interest income		0		0
Mortgage banking income		0		0
Other noninterest income		0		0
Included in unrealized net holding gains (losses) in other comprehensive income (loss)		0		(9)
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		(52)		(53)
Transfers into Level 3		0		0
Transfers out of Level 3		0		(57)
Ending balance		0		0
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period		0		0
Other Securities [Member]
Beginning balance				7
Interest income				0
Mortgage banking income				0
Other noninterest income				0
Included in unrealized net holding gains (losses) in other comprehensive income (loss)				(1)
Purchases				0
Issuances				0
Sales				0
Settlements				(1)
Transfers into Level 3				0
Transfers out of Level 3				(5)
Ending balance		0		0
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period				0
Covered Securities [Member]
Beginning balance	1,023	1,059	984	954
Interest income	14	8	18	26
Mortgage banking income	0	0	0	0
Other noninterest income	0	0	0	0
Included in unrealized net holding gains (losses) in other comprehensive income (loss)	(22)	(4)	40	83
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	(33)	0	(60)	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	982	1,063	982	1,063
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period	14	8	18	26
Residential Mortgage Servicing Rights [Member]
Beginning balance	696	928	563	830
Interest income	0	0	0	0
Mortgage banking income	(168)	(89)	(119)	(77)
Other noninterest income	0	0	0	0
Included in unrealized net holding gains (losses) in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Issuances	50	40	134	126
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	578	879	578	879
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period	(130)	(60)	(38)	(20)
Net Derivatives [Member]
Beginning balance	30	7	59	(25)
Interest income	0	0	0	0
Mortgage banking income	89	43	185	26
Other noninterest income	0	0	0	0
Included in unrealized net holding gains (losses) in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Issuances	77	10	138	21
Sales	0	0	0	0
Settlements	(128)	(57)	(314)	(19)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	68	3	68	3
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period	68	3	68	3
Private Equity and Similar Investments
Beginning balance	281	272	261	266
Interest income	0	0	0	0
Mortgage banking income	0	0	0	0
Other noninterest income	(1)	7	4	15
Included in unrealized net holding gains (losses) in other comprehensive income (loss)	0	0	0	0
Purchases	28	7	52	12
Issuances	0	0	0	0
Sales	(6)	(30)	(18)	(36)
Settlements	(1)	(6)	2	(7)
Transfers into Level 3	0	1	0	1
Transfers out of Level 3	0	(4)	0	(4)
Ending balance	301	247	301	247
Change in unrealized gains (losses) included in earnings for the period, attributable to assets and liabilities still held at end of period	$ (2)	$ 5	$ 7	$ 12