2.2.0.25falsefalse40305 - Disclosure - Investment Securities (Gains and Losses Related to Investment Securities) (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010
USD ($)
USD ($) / shares
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USD ($)
USD ($) / shares
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USD ($)
USD ($) / shares
$Duration_1_1_2008_To_12_31_2008http://www.sec.gov/CIK0000093751duration2008-01-01T00:00:002008-12-31T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$5false0us-gaap_AvailableForSaleSecuritiesGrossR
ealizedGainsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse13300000001330falsetruefalsefalsefalse2truefalsefalse418000000418falsetruefalsefalsefalse3truefalsefalse100000000100falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 21
-Subparagraph a
falsefalse6false0us-gaap_AvailableForSaleSecuritiesGrossRealizedLossesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-1385000000-1385falsefalsefalsefalsefalse2truefalsefalse-50000000-50falsefalsefalsefalsefalse3truefalsefalse-32000000-32falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 21
-Subparagraph a
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16
falsefalse8false0stt_NoncreditPortionOfOtherThanTemporaryImpairmentssttfalsecreditdurationNoncredit portion of other-than-temporary impairments.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse420000000420[1]falsefalsefalsefalsefalse2truefalsefalse928000000928[1]falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNoncredit portion of other-than-temporary impairments.No authoritative reference available.falsefalse9false0us-gaap_MarketableSecuritiesGainLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-286000000-286falsefalsefalsefalsefalse2truefalsefalse141000000141falsefalsefalsefalsefalse3truefalsefalse-54000000-54falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain or loss of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain or loss which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transfe
rred to trading securities during the period. Additionally, this item would include any losses recognized for other than temporary impairments of the subject investments in debt and equity securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 7
-Article 5
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13, 22
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Id>1truefalsefalse-203000000-203falsefalsefalsefalsefalse2truefalsefalse-151000000-151falsefalsefalsefalsefalse3truefalsefalse-122000000-122falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryImpairment associated with expected credit lossesNo authoritative reference available.falsefalse11false0stt_InvestmentsImpairmentAssociatedWithManagementsIntentNotToSellImpairedInvestmentsPriorToRecoveryInValuesttfalsedebitdurationInvestments Impairment associated with managements intent not to sell impaired investments prior to recovery in valuefalsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-1000000-1falsefalsefalsefalsefalse2truefalsefalse-54000000-54falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryInvestments Impairment associated with managements intent not to sell impaired investments prior to recovery in valueNo authoritative reference available.falsefalse12false0stt_ImpairmentAssociatedWithAdverseChangesInTimingOfExpectedFutureCashFlowssttfalsedebitdurationImpairment associated with adverse changes in timing of expected future cash flowsfalsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse<
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16
truefalse1
Pursuant to new GAAP adopted on April 1, 2009, these losses were recorded, net of related taxes, as component of other comprehensive income; see note 13. 39Investment Securities (Gains and Losses Related to Investment Securities) (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
