Derivative Financial Instruments And Hedging Activities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	$ 3,597	$ 3,542
Derivative asset, Fair value	16	12
Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	10,469	9,771
Derivative liability, Fair value	342	312
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	0	0
Derivative asset, Fair value	0	0
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Other Liabilities [Member] \| Interest Rate Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	8,950	7,700
Derivative liability, Fair value	317	276
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member] \| Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	3,597	3,542
Derivative asset, Fair value	16	12
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Assets [Member] \| Foreign Currency Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	0	0
Derivative asset, Fair value	0	0
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Liabilities [Member] \| Interest Rate Swaps [Member] \| Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	717	1,280
Derivative liability, Fair value	1	3
Designated as Hedging Instrument [Member] \| Cash Flow Hedging [Member] \| Other Liabilities [Member] \| Foreign Currency Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	802	791
Derivative liability, Fair value	24	33
Not Designated as Hedging Instrument [Member] \| Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	29,441	20,712
Derivative asset, Fair value	172	159
Not Designated as Hedging Instrument [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member] \| Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	15,455	8,667
Derivative asset, Fair value	74	55
Not Designated as Hedging Instrument [Member] \| Other Assets [Member] \| Interest Rate Options [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	13,369	10,469
Derivative asset, Fair value	33	26
Not Designated as Hedging Instrument [Member] \| Other Assets [Member] \| Foreign Currency Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, Notional amount	617	1,576
Derivative asset, Fair value	65	78
Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	30,738	20,602
Derivative liability, Fair value	103	64
Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member] \| Interest Rate Swaps [Member] \| Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	14,225	8,337
Derivative liability, Fair value	55	36
Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member] \| Interest Rate Options [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	15,101	12,146
Derivative liability, Fair value	33	26
Not Designated as Hedging Instrument [Member] \| Other Liabilities [Member] \| Foreign Currency Swaps [Member] \| Level 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, Notional amount	1,412	119
Derivative liability, Fair value	$ 15	$ 2

Nominal or face amount used to calculate payments on the derivative asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5579245-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6519104

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+ References

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+ References

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+ References

No definition available.

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