Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Mortgage servicing rights	$ 1,589		$ 1,351
Other Intangible Assets [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Asset Useful Life	1 year
Other Intangible Assets [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Asset Useful Life	9 years
Other Intangible Assets [Member] | Weighted Average [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Asset Useful Life	6 years
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member]
Finite-Lived Intangible Assets [Line Items]
Mortgage servicing rights	$ 526	$ 552	$ 506
Mortgage Servicing Rights [Member] | Minimum [Member] | Commercial Mortgage [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Asset Useful Life		5 years
Mortgage Servicing Rights [Member] | Maximum [Member] | Commercial Mortgage [Member]
Finite-Lived Intangible Assets [Line Items]
Finite Lived Intangible Asset Useful Life		10 years