2.2.0.25falsefalse123 - Disclosure - Comprehensive Income - Additional Information (Detail)truefalseIn Millionsfalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011
USD ($)
USD ($) / shares
$eol_PE1341----1110-Q0005_STD_90_20110331_0http://www.sec.gov/CIK0000080424duration2011-01-01T00:00:002011-03-31T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170iso4217_USD_per_sharesDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instanceshares0sharesStandardhttp://www.xbrl.org/2003/instanceshares0USDUSD$2falsefalseUSDfalsefalse1/1/2010 - 3/31/2010
USD ($)
USD ($) / shares
$eol_PE1341----1110-Q0005_STD_90_20100331_0http://www.sec.gov/CIK0000080424duration2010-01-01T00:00:002010-03-31T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170iso4217_USD_per_sharesDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instanceshares0sharesStandardhttp://www.xbrl.org/2003/instanceshares0USDUSD$3falsefalseUSDfalsefalse7/1/2010 - 3/31/2011
USD ($)
USD ($) / shares
$eol_PE1341----1110-Q0005_STD_274_20110331_0http://www.sec.gov/CIK0000080424duration2010-07-01T00:00:002011-03-31T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170iso4217_USD_per_sharesDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instanceshares0sharesStandardhttp://www.xbrl.org/2003/instanceshares0USDUSD$4falsefalseUSDfalsefalse7/1/2009 - 3/31/2010
USD ($)
USD ($) / shares
$eol_PE1341----1110-Q0005_STD_274_20100331_0http://www.sec.gov/CIK0000080424duration2009-07-01T00:00:002010-03-31T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170iso4217_USD_per_sharesDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instanceshares0sharesStandardhttp://www.xbrl.org/2003/instanceshares0USDUSD$5false0us-gaap_ComprehensiveIncomeNetOfTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse47340000004734falsetruefalsefalsefalse2truefalsefalse772000000772falsetruefalsefalsefalse3truefalsefalse1361400000013614falsetruefalsefalsefalse4truefalsefalse98600000009860falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A5
-Appendix A
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 30
Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(3)
Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 8, 9, 10, 11, 12, 13, 14
falsefalse41Comprehensive Income - Additional Information (Detail) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
