2.2.0.25truefalse42201 - Disclosure - Income Taxes (Narrative) (Details)truefalsefalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010
USD ($)
USD ($) / shares
$Duration_1_1_2010_To_12_31_2010http://www.sec.gov/CIK0000093751duration2010-01-01T00:00:002010-12-31T00:00:00Unit15Standardhttp://xbrl.us/us-types/2009-01-31sqftxbrlus0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse1/1/2009 - 12/31/2009
USD ($)
USD ($) / shares
$Duration_1_1_2009_To_12_31_2009http://www.sec.gov/CIK0000093751duration2009-01-01T00:00:002009-12-31T00:00:00Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit14Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$3falsefalseUSDfalsefalse1/1/2008 - 12/31/2008
USD ($)
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$2false0us-gaap_IncomeTaxExpenseBenefitExtraordi
naryItemsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse24100000002410000000falsetruefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) allocated to income (loss) from extraordinary items.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 46
falsefalse3false0stt_IncomeTaxExpenseRelatedToNetGainsFromSalesOfInvestmentSecuritiessttfalsedebitdurationIncome tax expense related to net gains from sales of investment securitiesfalsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse-98000000-98000000falsefalsefalsefalsefalse2truefalsefalse147000000147000000falsefalsefalsefalsefalse3truefalsefalse2700000027000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncome tax expense related to net gains from sales of investment securitiesNo authoritative reference available.falsefalse4false0us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeignus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse
DisplayZeroAsNone>13400000001340000000falsefalsefalsefalsefalse2truefalsefalse801000000801000000falsefalsefalsefalsefalse3truefalsefalse11100000001110000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of earnings (loss) from continuing operations before income taxes that is attributable to foreign operations, which is defined as income (loss) generated from operations located outside the entity's country of domicile.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Subparagraph 1(i)
-Article 4
falsefalse5false0us-gaap_RetainedEarningsUnappropriatedus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse15000000001500000000falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse<
Id>3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryA segregation of retained earnings which is available for dividend distribution. Earnings not paid out as dividends but instead reinvested in the core business or used to pay off debt. Unappropriated profit is part of shareholder equity. Also called Cumulative distributions or earned surplus or accumulated earnings or unappropriated profit.
Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 31
-Article 5
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 24
-Subparagraph a(4)
-Article 7
falsefalse6false0us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse2600000026000000falsefalsefalsefalsefalse2truefalsefalse1600000016000000falsefalsefalsefalsefalse3fa
lsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe sum of the tax effects as of the balance sheet date of the amount of excesses of tax deductions over gross income in a year which cannot be used on the tax returns in the current year but can be carried forward to reduce taxable income or income taxes payable in a future year, for which there must be sufficient tax-basis income to utilize a portion or all of
the carryforward amount to realize the deferred tax asset.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 289
falsefalse7false0stt_TaxPositionsForWhichUltimateDeductibilityIsHighlyCertainButTimeIsUncertainsttfalsedebitdurationTax positions for which the ultimate deductibility is highly certain but time is uncertainfalsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse354000000354000000falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTax positions for which the ultimate deductibility is highly certain but time is uncertainNo authoritative reference available.falsefalse8false0us-gaap_IncomeTaxExaminationInterestExpenseus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse
DisplayZeroAsNone>00falsefalsefalsefalsefalse2truefalsefalse30000003000000falsefalsefalsefalsefalse3truefalsefa
lse2200000022000000falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of estimated interest recognized in the period arising from income tax examinations.No authoritative reference available.falsefalse9false0us-gaap_IncomeTaxExaminationIntere
stAccruedus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse6500000065000000falsefalsefalsefalsefalse2truefalsefalse6500000065000000falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of estimated interest accrued as of the balance sheet date arising from income tax examinations.No authoritative reference available.falsefalse10false0us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthoritiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse3300000033000000falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalse
falseMonetaryxbrli:monetaryItemTypemonetaryThe gross amount of decreases in unrecognized tax benefits resulting from settlements with taxing authorities.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 48
-Paragraph 21
-Subparagraph a(3)
falsefalse11false0us-gaap_OperatingLossCarryforwardsExpirationDatesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse002011falsefalsefalsefalsefalse2falsefalsefalse002017falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe expiration date of each operating loss carryforward included in total operating loss carryforwards, or the applicable range of such expiration dates.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 48
-Subparagraph a
falsefalse12false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.statestreet.com/taxonomy/role/disclosureincometaxesnarrativedetails1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalse4falsefalseUSDtruefalse{us-gaap_OperatingLossCarryforwardsByTaxAuthorityAxis} : IRS audit of the tax years 2000 - 2006 [Member]
1/1/2010 - 12/31/2010
USD ($)
$Duration_1_1_2010_To_12_31_20104426http://www.sec.gov/CIK0000093751duration2010-01-01T00:00:002010-12-31T00:00:00falsefalseIRS audit of the tax years 2000 - 2006 [Member]us-gaap_OperatingLossCarryforwardsByTaxAuthorityAxisxbrldihttp://xbrl.org/2006/xbrldistt_IrsAuditOfTaxYearsTwoThousandToTwoThusandSixMemberus-gaap_OperatingLossCarryforwardsByTaxAuthorityAxisexplicitMemberUnit12Standard
UnitType>http://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse13false0us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuth
oritiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse336000000336000000falsetruefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe gross amount of decreases in unrecognized tax benefits resulting from settlements with taxing authorities.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 48
-Paragraph 21
-Subparagraph a(3)
falsefalse312Income Taxes (Narrative) (Details) (USD $)NoRoundingUnKnownUnKnownUnKnownfalsetrue