Goodwill and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Intangible Assets By Major Class [Line Items]
Goodwill	$ 48,057	$ 48,067	$ 48,175	$ 48,131	$ 48,208	$ 48,188
Mortgage servicing rights	9,335	7,949	7,614	7,118	8,039	7,223
Other intangible assets:
Other intangible assets	1,951		2,235
Purchased Credit Card Relationships [Member]
Other intangible assets:
Other intangible assets	221		295
Other credit card- related intangibles [Member]
Other intangible assets:
Other intangible assets	201		229
Core Deposit Intangibles [Member]
Other intangible assets:
Other intangible assets	255		355
Other intangibles [Member]
Other intangible assets:
Other intangible assets	$ 1,274		$ 1,356