Goodwill and Other Intangible Assets (Commercial Mortgage Servicing Rights) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance		$ 1,997	$ 2,216
Intangible assets, ending balance		1,997	2,216
Mortgage Servicing Rights [Member]
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance		1,482	1,636
Intangible assets, ending balance		1,482	1,636
Beginning balance - valuation allowance			(88)
Ending balance - valuation allowance			(88)
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member]
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance	420	515	552
Additions	86
Amortization expense	(54)
Change in valuation allowance	73
Intangible assets, ending balance	525	515	552
Beginning balance - valuation allowance	(176)
Provision	(4)
Recoveries	76
Other	1
Ending balance - valuation allowance	(103)
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | From loans sold with servicing retained [Member]
Servicing Assets At Amortized Value [Line Items]
Additions	31
Mortgage Servicing Rights [Member] | Commercial Mortgage [Member] | Purchases [Member]
Servicing Assets At Amortized Value [Line Items]
Additions	$ 55