Investment Securities (Summary) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	$ 47,176	$ 49,447
Securities available for sale, unrealized gains	1,302	2,031
Securities available for sale, unrealized losses	(579)	(426)
Securities available for sale, fair value	47,899	51,052
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	46,879	49,080
Securities available for sale, unrealized gains	1,302	2,031
Securities available for sale, unrealized losses	(579)	(426)
Securities available for sale, fair value	47,602	50,685
Held-to-maturity securities, amortized cost	9,550	10,354
Held-to-maturity securities, unrealized gains	238	506
Held-to-maturity securities, unrealized losses	(39)
Held-to-maturity securities, fair value	9,749	10,860
Corporate Stocks And Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	297	367
Securities available for sale, fair value	297	367
US Treasury and Government Agencies Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,052
Held-to-maturity securities, amortized cost	234
Residential Mortgage-backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	23,915
Held-to-maturity securities, amortized cost	3,773
Residential Mortgage-backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	5,816
Securities available for sale, unrealized gains		314
State and Municipal [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,193
Held-to-maturity securities, amortized cost	639
Other Debt Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,733
Held-to-maturity securities, amortized cost	349
US Treasury and Government Agencies Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,052	2,868
Securities available for sale, unrealized gains	158	245
Securities available for sale, fair value	2,210	3,113
Held-to-maturity securities, amortized cost	234	230
Held-to-maturity securities, unrealized gains	21	47
Held-to-maturity securities, fair value	255	277
Residential Mortgage-backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	23,915	25,844
Securities available for sale, unrealized gains	514	952
Securities available for sale, unrealized losses	(181)	(12)
Securities available for sale, fair value	24,248	26,784
Held-to-maturity securities, amortized cost	3,773	4,380
Held-to-maturity securities, unrealized gains	84	202
Held-to-maturity securities, unrealized losses	(32)
Held-to-maturity securities, fair value	3,825	4,582
Residential Mortgage-backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	5,816	6,102
Securities available for sale, unrealized gains	292
Securities available for sale, unrealized losses	(256)	(309)
Securities available for sale, fair value	5,852	6,107
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	574	602
Securities available for sale, unrealized gains	22	31
Securities available for sale, unrealized losses	(1)
Securities available for sale, fair value	595	633
Held-to-maturity securities, amortized cost	1,262	1,287
Held-to-maturity securities, unrealized gains	57	87
Held-to-maturity securities, fair value	1,319	1,374
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	3,560	3,055
Securities available for sale, unrealized gains	135	210
Securities available for sale, unrealized losses	(16)	(1)
Securities available for sale, fair value	3,679	3,264
Held-to-maturity securities, amortized cost	2,193	2,582
Held-to-maturity securities, unrealized gains	42	85
Held-to-maturity securities, unrealized losses	(4)
Held-to-maturity securities, fair value	2,231	2,667
Asset Backed Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	6,036	5,667
Securities available for sale, unrealized gains	57	65
Securities available for sale, unrealized losses	(59)	(79)
Securities available for sale, fair value	6,034	5,653
Held-to-maturity securities, amortized cost	1,100	858
Held-to-maturity securities, unrealized gains	3	5
Held-to-maturity securities, unrealized losses	(3)
Held-to-maturity securities, fair value	1,100	863
State and Municipal [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,193	2,197
Securities available for sale, unrealized gains	64	111
Securities available for sale, unrealized losses	(40)	(21)
Securities available for sale, fair value	2,217	2,287
Held-to-maturity securities, amortized cost	639	664
Held-to-maturity securities, unrealized gains	19	61
Held-to-maturity securities, fair value	658	725
Other Debt Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,733	2,745
Securities available for sale, unrealized gains	60	103
Securities available for sale, unrealized losses	(26)	(4)
Securities available for sale, fair value	2,767	2,844
Held-to-maturity securities, amortized cost	349	353
Held-to-maturity securities, unrealized gains	12	19
Held-to-maturity securities, fair value	$ 361	$ 372

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-Publisher FASB

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References+ Details

- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References+ Details

- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References+ Details