This item represents the cost of equity securities before adjustments for other-than-temporary impairments recognized in earnings.

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- Definition

Investments in equity securities [Line Items]

+ Details

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- Definition

This item represents the total unrealized holding gain on marketable equity securities, at reporting date.

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- Definition

The number of shares of an equity securities investment that is in a gain position for which an other-than-temporary loss was not recorded.

+ Details

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- Definition

The number of shares of an equity securities investment that is in a loss position for which an other-than-temporary loss was recorded through earnings.

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- Definition

The term over which certain securities were in an unrealized loss position and the related loss was not recognized in earnings.

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- Definition

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

+ Details

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- Definition

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities.

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- Definition

The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

+ References

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 16B

-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 FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 7

-Footnote 2

-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 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 4: 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.

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Investments in equity securities - Narrative (Detail) (USD $) In Millions					3 Months Ended			9 Months Ended		3 Months Ended
	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2010 Equity Securities [Member]	Mar. 31, 2011 Equity Securities [Member] Wells Fargo and Company [Member]	Sep. 30, 2011 Insurance and Other [Member]	Mar. 31, 2011 Insurance and Other [Member]	Sep. 30, 2010 Insurance and Other [Member]	Sep. 30, 2011 Insurance and Other [Member]	Sep. 30, 2010 Insurance and Other [Member]	Mar. 31, 2011 Wells Fargo and Company [Member]
Investments in equity securities [Line Items]
Unrealized losses related to securities that have been in an unrealized loss position for more than 12 months			$ 531
Other-than-temporary impairment of securities					8	506	15	514	15	337
Number of shares in loss position before OTTI adjustment										103.6
Cost of investment in loss position before OTTI adjustment										3,621
Number of shares in gain position										255.4
Cost of investment in gain position										4,394
Unrealized gain	$ 24,646	$ 26,641		$ 3,704
Term over which certain securities were in an unrealized loss position								more than 12 months