Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Net Carrying Value	$ 1,844	$ 2,216
Customer-Related and Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,502	1,676
Accumulated amortization	(1,009)	(1,096)
Intangible Assets, Net Carrying Value	493	580	726
Mortgage Servicing Rights [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,351	2,620
Valuation allowance		(88)
Accumulated amortization		(896)
Intangible Assets, Net Carrying Value	$ 1,351	$ 1,636