Goodwill and Other Intangible Assets (Changes in Carrying Amounts of Goodwill Attributable to Each Operating Segment) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Goodwill, beginning balance	$ 6,804
Contingent consideration	6
Other adjustments	13
Goodwill, ending balance	6,823
Community Banking [Member]
Goodwill, beginning balance	4,900
Contingent consideration	0
Other adjustments	26
Goodwill, ending balance	4,926
Residential Mortgage Banking [Member]
Goodwill, beginning balance	7
Contingent consideration	0
Other adjustments	0
Goodwill, ending balance	7
Dealer Financial Services [Member]
Goodwill, beginning balance	111
Contingent consideration	0
Other adjustments	0
Goodwill, ending balance	111
Specialized Lending [Member]
Goodwill, beginning balance	99
Contingent consideration	0
Other adjustments	(2)
Goodwill, ending balance	97
Insurance Services [Member]
Goodwill, beginning balance	1,495
Contingent consideration	6
Other adjustments	(11)
Goodwill, ending balance	1,490
Financial Services [Member]
Goodwill, beginning balance	192
Contingent consideration	0
Other adjustments	0
Goodwill, ending balance	$ 192