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, 2012
Goodwill, beginning balance	$ 6,078
Other adjustments	(1)
Goodwill, ending balance	6,077
Community Banking [Member]
Goodwill, beginning balance	4,542
Other adjustments	0
Goodwill, ending balance	4,542
Residential Mortgage Banking [Member]
Goodwill, beginning balance	7
Other adjustments	0
Goodwill, ending balance	7
Dealer Financial Services [Member]
Goodwill, beginning balance	111
Other adjustments	0
Goodwill, ending balance	111
Specialized Lending [Member]
Goodwill, beginning balance	94
Other adjustments	0
Goodwill, ending balance	94
Insurance Services [Member]
Goodwill, beginning balance	1,132
Other adjustments	(1)
Goodwill, ending balance	1,131
Financial Services [Member]
Goodwill, beginning balance	192
Other adjustments	0
Goodwill, ending balance	$ 192