2.2.0.25falsefalse006100 - Disclosure - EQUITY INVESTMENT INCOME, NETtruefalsefalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) USD ($) / shares $c00012http://www.sec.gov/CIK0000072020duration2011-01-01T00:00:002011-03-31T00:00:00u000Standardhttp://www.xbrl.org/2003/iso4217USDiso42170u001Standardhttp://www.xbrl.org/2003/instancesharesxbrli0u002Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0gas_NotesToFinancialStatementsAbstractgasfalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseNotes to Financial Statements [Abstract]3false0us-gaap_EquityMethodInvestmentsTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<div><table style="FONT-SIZE: 10pt; FONT-FAMILY: times new roman" cellspacing="0" cellpadding="0" width="100%" align="center" border="0"><tr style="LINE-HEIGHT: 1.5" valign="top"><td style="WIDTH: 18pt"><div style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt"><font style="DISPLAY: inline; FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">10.</font></div></td><td><div align="left"><font style="DISPLAY: inline; FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">EQUITY INVESTMENT INCOME, NET</font></div></td></tr></table></div><div style="DISPLAY: block; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.5"><br /></div><div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.5; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Equity investment income includes investment income from Triton of $4.2 million and $1.4 million for the three months ended March 31, 2011 and 2010, respectively.&#160;&#160;Nicor received cash distributions from equity investees for the three months ended March 31, 2011 and 2010 of $4.1 million and $2.5 million, respectively.</font></div>10.EQUITY INVESTMENT INCOME, NETEquity investment income includes investment income from Triton of $4.2 million and $1.4 million for the three months endedfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis item represents disclosure of information related to equity method investments in common stock. The information which should be considered for disclosure includes: (a) the name of each investee or group of investments for which combined disclosure is appropriate, (2) the percentage ownership of common stock, (3) the difference, if any, between the carrying amount of an investment and the value of the underlying equity in the net assets and the accounting treatment of difference, if any, and (4) the aggregate value of each identified investment based on its quoted market price, if available.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 20 -Subparagraph a, b falsefalseEQUITY INVESTMENT INCOME, NET12EQUITY INVESTMENT INCOME, NETUnKnownUnKnownUnKnownUnKnownfalsetrue