2.2.0.25falsefalse41404 - Disclosure - Fair Value (Reported Amounts and Estimated Fair Values for Financial Instruments) (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse12/31/2010
USD ($)
USD ($) / shares
$As_Of_12_31_2010http://www.sec.gov/CIK0000093751instant2010-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit14Divide
http://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2falsefalseUSDfalsefalse12/31/2009
USD ($)
USD ($) / shares
$As_Of_12_31_2009http://www.sec.gov/CIK0000093751instant2009-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit14Divide
http://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$5false0us-gaap_HeldToMaturitySecuritiesFairValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1257600000012576falsetruefalsefalsefalse2truefalsefalse2092800000020928falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 137
falsefalse6false0us-gaap_HeldToMaturitySecuritiesus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1224900000012249falsefalsefalsefalsefalse2truefalsefalse2087700000020877falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFor an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity; such investments are measured at amortized cost (carrying value). The held-to-maturity category is for those securities that the Entity has the positive intent and ability to hold until maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 3
-Section A
-Paragraph 4, 5
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 17
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 7, 8, 9, 10, 11
falsefalse7false0stt_FairValueOfNetLoansExcludingLoansCarriedAtFairValueAndLeasessttfalsedebitinstantFair Value Of Net Loans Excluding Loans Carried At Fair Value And Leasesfalsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1024200000010242falsefalsefalsefalsefalse2truefalsefalse87290000008729falsefalsefalsefals
efalseMonetaryxbrli:monetaryItemTypemonetaryFair Value Of Net Loans Excluding Loans Carried At Fair Value And LeasesNo authoritative reference available.falsefalse8false0stt_NetLoansExcludingLeasesAtReportedAmountsttfalsecreditinstantNet Loans Excluding Leases, at Reported Amountfalsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1038700000010387falsefalsefalsefalsefalse2truefalsefalse90130000009013falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNet Loans Excluding Leases, at Reported AmountNo authoritative reference available.falsefalse9false0us-gaap_DebtInstrumentFairValueus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse84980000008498falsefalsefalsefalsefalse2truefalsefalse87150000008715falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryEstimated fair value of the debt instrument at the balance-sheet date.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 107
-Paragraph 10
falsefalse10false0us-gaap_LongTermDebtus-gaaptruecreditinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse85500000008550falsetruefalsefalsefalse2truefalsefalse88380000008838falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncluding current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 7
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 20, 22
-Article 5
falsefalse26Fair Value (Reported Amounts and Estimated Fair Values for Financial Instruments) (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
