Securities Available for Sale, Major Categories (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 217,001	$ 215,571
Gross unrealized gains	13,702	10,211
Gross unrealized losses	(1,353)	(3,169)
Securities available for sale	229,350	222,613
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	214,674	212,642
Gross unrealized gains	13,223	9,660
Gross unrealized losses	(1,299)	(3,106)
Securities available for sale	226,598	219,196
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	1,829	6,920
Gross unrealized gains	40	59
Gross unrealized losses	0	(11)
Securities available for sale	1,869	6,968
US States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	36,417	32,307
Gross unrealized gains	1,994	1,169
Gross unrealized losses	(486)	(883)
Securities available for sale	37,925	32,593
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	130,309	127,105
Gross unrealized gains	8,969	6,987
Gross unrealized losses	(467)	(1,352)
Securities available for sale	138,811	132,740
Federal agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	97,342	92,279
Gross unrealized gains	5,381	4,485
Gross unrealized losses	(10)	(10)
Securities available for sale	102,713	96,754
Residential [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	14,754	16,997
Gross unrealized gains	1,845	1,253
Gross unrealized losses	(61)	(414)
Securities available for sale	16,538	17,836
Commercial [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	18,213	17,829
Gross unrealized gains	1,743	1,249
Gross unrealized losses	(396)	(928)
Securities available for sale	19,560	18,150
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	19,101	17,921
Gross unrealized gains	1,254	769
Gross unrealized losses	(92)	(286)
Securities available for sale	20,263	18,404
Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	9,890	8,650
Gross unrealized gains	475	298
Gross unrealized losses	(140)	(349)
Securities available for sale	10,225	8,599
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	17,128	19,739
Gross unrealized gains	491	378
Gross unrealized losses	(114)	(225)
Securities available for sale	17,505	19,892
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	2,327	2,929
Gross unrealized gains	479	551
Gross unrealized losses	(54)	(63)
Securities available for sale	2,752	3,417
Perpetual preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	1,924	2,396
Gross unrealized gains	240	185
Gross unrealized losses	(47)	(54)
Securities available for sale	2,117	2,527
Other equity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	403	533
Gross unrealized gains	239	366
Gross unrealized losses	(7)	(9)
Securities available for sale	$ 635	$ 890

For an unclassified balance sheet, this item represents investments in debt and equity securities which are 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

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15E

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15D

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-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 Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-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 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ 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