Goodwill and Other Intangible Assets (Identifiable Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Gross carrying amount	$ 1,703		$ 1,413
Accumulated amortization	(1,020)		(969)
Net carrying amount	683		444
Core Deposit Intangibles [Member]
Gross carrying amount	626		626
Accumulated amortization	(502)		(484)
Net carrying amount	124		142
Other Identifiable Intangible Assets [Member]
Gross carrying amount	1,077	[1]	787	[1]
Accumulated amortization	(518)	[1]	(485)	[1]
Net carrying amount	$ 559	[1]	$ 302	[1]

[1] Other identifiable intangibles are primarily customer relationship intangibles.