Goodwill and Other Intangible Assets (Commercial Mortgage Servicing Rights) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance			$ 1,844
Intangible assets, ending balance	2,216		1,844
Mortgage Servicing Rights [Member]
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance			1,351
Intangible assets, ending balance	1,636		1,351
Ending balance - valuation allowance	(88)
Mortgage Servicing Rights [Member] \| Commercial Mortgage [Member]
Servicing Assets At Amortized Value [Line Items]
Intangible assets, beginning balance	420	468	506
Additions	138	73
Amortization expense	(97)	(142)
Change in valuation allowance	88	21
Intangible assets, ending balance	549	420	506
Beginning balance - valuation allowance	(176)	(197)
Provision	(21)	(46)
Recoveries	108	43
Other	1	24
Ending balance - valuation allowance	(88)	(176)
Mortgage Servicing Rights [Member] \| Commercial Mortgage [Member] \| From loans sold with servicing retained [Member]
Servicing Assets At Amortized Value [Line Items]
Additions	53	45
Mortgage Servicing Rights [Member] \| Commercial Mortgage [Member] \| Purchases [Member]
Servicing Assets At Amortized Value [Line Items]
Additions	$ 85	$ 28

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

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Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

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The charge against the valuation allowance related to a servicing asset that is subsequently measured using the amortization method.

+ References

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Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss.

+ References

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The net increase (decrease) in the valuation allowance for servicing assets subsequently measured using the amortization method.

+ References

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This item represents the contra-account activity for provisions recognized for impairments of servicing assets which is offset against the value of servicing assets to arrive at a net carrying value as of the date of the statement of financial position.

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This item represents the contra-account activity for recoveries recognized for impairments of servicing assets which is offset against the value of servicing assets to arrive at a net carrying value as of the date of the statement of financial position.

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