2.2.0.25falsefalse002010 - Statement - Consolidated Balance Sheets (unaudited) (Parenthetical)truefalseIn Millions, except Per Share datafalse1falsefalseUSDfalsefalse3/31/2011 USD ($) USD ($) / shares $c20110331http://www.sec.gov/CIK0000072207instant2011-03-31T00:00:000001-01-01T00:00:00U004Standardhttp://www.xbrl.org/2003/instancepurexbrli0U001Standardhttp://www.xbrl.org/2003/iso4217USDiso42170U002Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0U003Standardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse12/31/2010 USD ($) USD ($) / shares $c20101231http://www.sec.gov/CIK0000072207instant2010-12-31T00:00:000001-01-01T00:00:00U003Standardhttp://www.xbrl.org/2003/instancesharesxbrli0U001Standardhttp://www.xbrl.org/2003/iso4217USDiso42170U002Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0U004Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$4true0us-gaap_StockholdersEquityAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseShareholders' Equity5false0us-gaap_PreferredStockParOrStatedValuePerShareus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse1.001.00falsetruefalsefalsefalse2truefalsefalse1.001.00falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalFace amount or stated value per share of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer); generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 3, 4, 5, 6, 7, 8 falsetruePreferred Stock, Par Value Per Share (in dollars per share)6false0us-gaap_RedeemablePreferredStockSharesAuthorizedus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse40000004falsefalsefalsefalsefalse2truefalsefalse40000004falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesThe maximum number of redeemable preferred shares permitted to be issued by an entity's charter and bylaws.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 3, 4, 5, 6, 7, 8 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 28 -Article 5 falsefalsePreferred Stock, Shares Authorized (in shares)7false0us-gaap_CommonStockParOrStatedValuePerShareus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse3.333.33falsetruefalsefalsefalse2truefalsefalse3.333.33falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalFace amount or stated value of common stock per share; generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 falsetrueCommon Stock, Par Value Per Share (in dollars per share)8false0us-gaap_CommonStockSharesAuthorizedus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse250000000250falsefalsefalsefalsefalse2truefalsefalse250000000250falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesThe maximum number of common shares permitted to be issued by an entity's charter and bylaws.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 falsefalseCommon Shares, Shares Authorized (in shares)9false0us-gaap_CommonStockSharesIssuedus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse196000000196falsefalsefalsefalsefalse2truefalsefalse195000000195falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesTotal number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 falsefalseCommon Stock, Shares Issued (in shares)10false0us-gaap_TreasuryStockSharesus-gaaptruenainstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse1900000019falsefalsefalsefalsefalse2truefalsefalse1900000019falsefalsefalsefalsefalseSharesxbrli:sharesItemTypesharesNumber of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 falsefalseTreasury Stock, Shares (in shares)27Consolidated Balance Sheets (unaudited) (Parenthetical) (USD $)UnKnownMillionsNoRoundingUnKnownfalsetrue