Derivative Financial Instruments (Effect on the Consolidated Statements of Income) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Not designated as hedges
Not Designated as Hedges:
Pre-tax Gain (Loss) Recognized in Income	$ 102	$ 87	$ 269
Cash flow hedges \| Interest rate contracts
Cash Flow Hedges:
Pre-tax Gain (Loss) Recognized in OCI	(24)	(130)	(172)
Cash flow hedges \| Interest rate contracts \| Interest expense
Cash Flow Hedges:
Pre-tax Gain (Loss) Reclassified from AOCI into Income	(11)	(83)	(82)
Fair value hedges \| Interest rate contracts
Fair Value Hedges:
Pre-tax Gain (Loss) Recognized in Income	208	259	211
Fair value hedges \| Interest rate contracts \| Interest income
Fair Value Hedges:
Pre-tax Gain (Loss) Recognized in Income	(18)	(20)	(22)
Fair value hedges \| Interest rate contracts \| Interest expense
Fair Value Hedges:
Pre-tax Gain (Loss) Recognized in Income	226	279	233
Client-related and other risk management \| Interest rate contracts \| Other income \| Not designated as hedges
Not Designated as Hedges:
Pre-tax Gain (Loss) Recognized in Income	52	27	18
Client-related and other risk management \| Foreign exchange contracts \| Other income \| Not designated as hedges
Not Designated as Hedges:
Pre-tax Gain (Loss) Recognized in Income	11	21	16
Mortgage banking \| Interest rate contracts \| Mortgage banking income \| Not designated as hedges
Not Designated as Hedges:
Pre-tax Gain (Loss) Recognized in Income	8	7	(16)
MSRs \| Interest rate contracts \| Mortgage banking income \| Not designated as hedges
Not Designated as Hedges:
Pre-tax Gain (Loss) Recognized in Income	$ 31	$ 32	$ 251

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

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-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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