Derivative Instruments and Other Financial Instruments Used For Hedging (Details 3) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Mar. 31, 2015
Cash Flow Hedges
Amount and location of net gains and losses
Amount of Gain or (Loss) Recognized in OCI on Derivative Instruments (Effective Portion)	$ 266	$ 119
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	43	33
Cash Flow Hedges \| Interest rate derivative contracts
Amount and location of net gains and losses
Amount of Gain or (Loss) Recognized in OCI on Derivative Instruments (Effective Portion)	266	119
Cash Flow Hedges \| Interest rate derivative contracts \| Interest income
Amount and location of net gains and losses
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	43	32
Cash Flow Hedges \| Interest rate derivative contracts \| Interest expense
Amount and location of net gains and losses
Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	1
Cash Flow Hedges \| Interest rate derivative contracts \| Noninterest expense \| Maximum
Amount and location of net gains and losses
Gain or (Loss) Recognized in Income on Derivative Instruments (Ineffective Portion and Amount Excluded from Effectiveness Testing)	1	1
Fair value hedges \| Interest rate derivative contracts
Amount and location of net gains and losses
Derivative	7	5
Hedged Item	(7)	(4)
Hedge Ineffectiveness	0	1
Designated as Hedging Instrument \| Fair value hedges \| Interest rate derivative contracts
Amount and location of net gains and losses
Derivative	7	5
Hedged Item	(7)	(4)
Hedge Ineffectiveness	$ 0	$ 1

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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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=56946850&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=56946850&loc=SL5624177-113959

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- Definition

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ 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 (d)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1),(2)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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- Definition

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)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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