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USD ($)
USD ($) / shares
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USD ($)
USD ($) / shares
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USD ($)
USD ($) / shares
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12/31/2010
USD ($)
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12/31/2009
USD ($)
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12/31/2008
USD ($)
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12/31/2010
USD ($)
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12/31/2009
USD ($)
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12/31/2008
USD ($)
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12/31/2010
USD ($)
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12/31/2009
USD ($)
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12/31/2008
USD ($)
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12/31/2010
USD ($)
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12/31/2009
USD ($)
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12/31/2008
USD ($)
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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12/31/2010
USD ($)
$I2010_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberhttp://www.sec.gov/CIK0000018230instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseU.S. governmental agency mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$17falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : U.S. governmental agency mortgage-backed securities
12/31/2009
USD ($)
$I2009_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberhttp://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseU.S. governmental agency mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$18falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : U.S. governmental agency mortgage-backed securities
12/31/2008
USD ($)
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-Name Statement of Financial Accounting Standard (FAS)
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-Name Statement of Financial Accounting Standard (FAS)
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12/31/2010
USD ($)
$I2010_ResidentialMortgageBackedSecuritiesMemberhttp://www.sec.gov/CIK0000018230instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseResidential mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$20falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Residential mortgage-backed securities
12/31/2009
USD ($)
$I2009_ResidentialMortgageBackedSecuritiesMemberhttp://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseResidential mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_ResidentialMortgageBackedSecuritiesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$21falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Residential mortgage-backed securities
12/31/2008
USD ($)
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-Name FASB Staff Position (FSP)
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-Footnote 2
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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12/31/2010
USD ($)
$I2010_CommercialMortgageBackedSecuritiesMemberhttp://www.sec.gov/CIK0000018230instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseCommercial mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CommercialMortgageBackedSecuritiesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$23falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Commercial mortgage-backed securities
12/31/2009
USD ($)
$I2009_CommercialMortgageBackedSecuritiesMemberhttp://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseCommercial mortgage-backed securitiesus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CommercialMortgageBackedSecuritiesMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$24falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Commercial mortgage-backed securities
12/31/2008
USD ($)
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-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 7
-Footnote 2
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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12/31/2010
USD ($)
$I2010_LargeCapitalizationMemberhttp://www.sec.gov/CIK0000018230instant2010-12-31T00:00:000001-01-01T00:00:00falsefalseLarge capitalization valueus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldicat_LargeCapitalizationMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$26falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Large capitalization value
12/31/2009
USD ($)
$I2009_LargeCapitalizationMemberhttp://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseLarge capitalization valueus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldicat_LargeCapitalizationMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$27falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Large capitalization value
12/31/2008
USD ($)
$I2008_LargeCapitalizationMemberhttp://www.sec.gov/CIK0000018230instant2008-12-31T00:00:000001-01-01T00:00:00falsefalseLarge capitalization valueus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldicat_LargeCapitalizationMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse42true0us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItemsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringLine items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.falsefalse43false0us-gaap_AvailableForSaleSecuritiesAmortizedCostus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse100000000100falsefalsefalsefalsefalse2truefalsefalse7600000076falsefalsefalsefalsefalse3truefalsefalse126000000126falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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12/31/2010
USD ($)
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12/31/2009
USD ($)
$I2009_SmallerCompanyMemberhttp://www.sec.gov/CIK0000018230instant2009-12-31T00:00:000001-01-01T00:00:00falsefalseSmaller company growthus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldicat_SmallerCompanyMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$30falsefalseUSDtruefalse{us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis} : Smaller company growth
12/31/2008
USD ($)
$I2008_SmallerCompanyMemberhttp://www.sec.gov/CIK0000018230instant2008-12-31T00:00:000001-01-01T00:00:00falsefalseSmaller company growthus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisxbrldihttp://xbrl.org/2006/xbrldicat_SmallerCompanyMemberus-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalse47true0us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItemsus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringLine items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.falsefalse48false0us-gaap_AvailableForSaleSecuritiesAmortizedCostus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse2300000023falsefalsefalsefalsefalse2truefalsefalse1900000019falsefalsefalsefalsefalse3truefalsefalse2000000020falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 7
-Footnote 2
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19
falsefalse49false0cat_AvailableForSaleSecuritiesUnrealizedGainsLossesNetcatfalsecreditinstantThis item represents the net unrealized gains (losses) for securities which are categorized neither as held-to-maturity nor...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse80000008falsefalsefalsefalsefalse2truefalsefalse50000005falsefalsefalsefalsefalse3truefalsefalse-2000000-2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the net unrealized gains (losses) for securities which are categorized neither as held-to-maturity nor trading securities. Such net unrealized gains (losses) are the difference of the fair value of the Available-for-sale Securities as compared to their carrying value as of the reporting date.No authoritative reference available.falsefalse50false0us-gaap_AvailableForSaleSecuritiesFairValueDisclosureus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse3100000031falsetruefalsefalsefalse2truefalsefalse2400000024falsetruefalsefalsefalse3truefalsefalse1800000018falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b
falsefalse349Available-for-sale securities (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
