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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_EffectiveIncomeTaxRateReconcilia
tionAtFederalStatutoryIncomeTaxRateus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truetruefalse0.350.35falsefalsefalsefalsefalse2truetruefalse0.350.35falsefalsefalsefalsefalse3truetruefalse0.350.35falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate shall be the regular tax rate if there are alternative tax systems.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 47
falsefalse6false0us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truetruefalse0.0120.012falsefalsefalsefalsefalse2truetruefalse0.0170.017falsefalsefalsefalsefalse3truetruefalse0.0340.034falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the state and local income tax expense (benefit), net of the federal tax benefit (expense) thereon, recorded during the period.No authoritative reference available.falsefalse7false0us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncomeus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truetrue
false-0.036-0.036falsefalsefalsefalsefalse2truetruefalse-0.031-0.031falsefalsefalsefalsefalse3truetruefalse-0.02-0.02falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to income that is exempt from income taxes under enacted tax laws.No authoritative reference available.falsefalse8false0us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truetruefalse-0.013-0
.013falsefalsefalsefalsefalse2truetruefalse-0.016-0.016falsefalsefalsefalsefalse3truetruefalse-0.009-0.009falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe sum of the differences between the effective income tax rate and domestic federal statutory income tax rate that can be explained by all tax credits generated or utilized under enacted tax laws during the period.No authoritative reference available.falsefalse9false0
us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferentialus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truetruefalse-0.036-0.036falsefalsefalsefalsefalse2truetruefalse-0.05-0.05falsefalsefalsefalsefalse3truetruefalse-0.014-0.014falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe portion of the difference between the effective income tax rate and domestic federal statutory income tax rate that can be explained by the difference between statutory income tax rates in foreign jurisdictions and the domestic federal statutory income tax rate recorded during the period.No authoritative reference available.falsefalse10false0us-gaap_IncomeTaxReconciliationOtherReconcilingItemsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-2.3-2.3[1]falsetruefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe sum of other amounts reflected in the reconciliation of the statutory tax provision (benefit) to the actual tax provision (benefit).No authoritative reference available.falsefalse11false0stt_EffectiveIncomeTaxRateReconciliationProvisionsRelatedToLiloAndSiloTransactionssttfalsenadurationEffective Income Tax Rate Reconciliation Provisions Related To LILO And SILO Transactionsfalsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.0010.001falsefalsefalsefalsefalse3truetruefalse0.0240.024<
IsIndependantCurrency>falsefalsefalsefalsefalseOtherus-types:percentItemTypepureEffective Income Tax Rate Reconciliation Provisions Related To LILO And SILO TransactionsNo authoritative reference available.falsefalse12false0us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOtherus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.010.01falsefalsefalsefalsefalse3falsetruefalse00falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to nondeductible expenses under enacted tax laws, or differences in the methodologies used to determine expense amounts for financial statements prepared in accordance with generally accepted accounting principles, not otherwise listed in the existing taxonomy.No authoritative reference available.falsefalse13false0us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustmentsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsetruefalse00falsefalsefalsefalsefalse2truetruefalse0.0050.005falsefalsefalsefalsefalse3truetruefalse-0.003-0.003falsefalsefalsefalsefalseOtherus-types:percentItemTypepureThe portion of the difference between the effective income tax rate and domestic federal statutory income tax rate attributable to all other items not otherwise listed in the existing taxonomy.No authoritative reference available.falsefalse14false0us-gaap_EffectiveIncomeTaxRateContinuingOperationsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truetruefalse0.2540.254falsefalsefalsefalsefalse2truetruefalse0.2860.286falsefalsefalsefalsefalse3truetruefalse0.3620.362falsefalsefalsefalsefalseOtherus-types:percentItemTypepureA ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 47
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Subparagraph 2
-Article 4
truefalse1
Represented the net effect of a discrete tax benefit associated with the restructuring of former non-U.S. conduit assets and the partial write-off of a deferred tax asset associated with certain of the investment securities sold in connection with the repositioning of the investment portfolio. 310Income Taxes (Schedule of Reconciliation of the U.S. Statutory Income Tax Rate to the Effective Tax Rate) (Details) (USD $)NoRoundingUnKnownUnKnownUnKnowntruetrue
