Goodwill and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Intangible Assets By Major Class [Line Items]
Goodwill	$ 48,067	$ 48,175	$ 48,208	$ 48,188
Mortgage servicing rights	7,949	7,614	8,039	7,223
Other intangible assets:
Other intangible assets	2,082	2,235
Purchased Credit Card Relationships [Member]
Other intangible assets:
Other intangible assets	242	295
Other credit card- related intangibles [Member]
Other intangible assets:
Other intangible assets	213	229
Core Deposit Intangibles [Member]
Other intangible assets:
Other intangible assets	305	355
Other intangibles [Member]
Other intangible assets:
Other intangible assets	$ 1,322	$ 1,356