2.2.0.25falsefalse0505 - Disclosure - Income Taxes (Tables)truefalsefalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010
USD ($)
USD ($) / shares
$Jan-01-2010_Dec-31-2010http://www.sec.gov/CIK0000092122duration2010-01-01T00:00:002010-12-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170PureStandardhttp://www.xbrl.org/2003/instancepurexbrli0USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0so_IncomeTaxesTablesAbstractsofalsenadurationIncome Taxes.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse| 1falsefalsefalse00falsefalsefalsefalsefalse | Otherxbrli:stringItemTypestringIncome Taxes.falsefalse
3false0so_DetailsOfIncomeTaxProvisionsTextBlocksofalsenadurationDetails of income tax provisions.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table1 - so:DetailsOfIncomeTaxProvisionsTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2008</td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="11"><i>(in millions)</i></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Federal —
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Current
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>42</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">771</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">628</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Deferred
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>898</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">40</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">177</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>940</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">811</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">805</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">State —
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Current
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(54</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td> </td>
<td align="right">100</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">72</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Deferred
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>140</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(15</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right">38</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>86</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">85</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">110</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Total
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>1,026</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">896</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">915</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringDetails of income tax provisions.No authoritative reference available.falsefalse
4false0so_TaxEffectsBetweenCarryingAmountsOfAssetsAndLiabilitiesTextBlocksofalsenadurationTax effects between the carrying amounts of assets and liabilities.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table2 - so:TaxEffectsBetweenCarryingAmountsOfAssetsAndLiabilitiesTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="76%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="7"><i>(in millions)</i></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Deferred tax liabilities —
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Accelerated depreciation
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>6,833</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">5,938</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Property basis differences
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>1,150</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">986</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Leveraged lease basis differences
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>263</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">251</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Employee benefit obligations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>485</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">384</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Under recovered fuel clause
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>179</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">271</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Premium on reacquired debt
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>78</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">100</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Regulatory assets associated with employee benefit obligations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>814</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">939</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Regulatory assets associated with asset retirement obligations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>509</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">486</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Other
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>246</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">216</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Total
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>10,557</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">9,571</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Deferred tax assets —
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Federal effect of state deferred taxes
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>386</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">302</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">State effect of federal deferred taxes
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>50</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">108</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Employee benefit obligations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>1,179</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">1,435</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Over recovered fuel clause
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>40</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">119</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Other property basis differences
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>119</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">132</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Deferred costs
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>100</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">65</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Cost of removal
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>52</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">109</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Unbilled revenue
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>126</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">96</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Other comprehensive losses
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>69</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">81</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Asset retirement obligations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>509</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">486</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Other
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>523</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">458</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Total
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>3,153</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">3,391</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Total deferred tax liabilities, net
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>7,404</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">6,180</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Portion included in prepaid expenses (accrued income taxes), net
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>117</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">229</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Deferred state tax assets
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>91</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">105</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Valuation allowance
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(58</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(59</td>
<td nowrap="nowrap">)</td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Accumulated deferred income taxes
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>7,554</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">6,455</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="9" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringTax effects between the carrying amounts of assets and liabilities.No authoritative reference available.falsefalse
5false0so_ApplicableUSFederalStatutoryRateToEarningsBeforeIncomeTaxesAndPreferredAndPreferenceDividendsOfSubsidiariesTextBlocksofalsenadurationApplicable U.S. federal statutory rate to earnings before income taxes and preferred and preference dividends of...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table3 - so:ApplicableUSFederalStatutoryRateToEarningsBeforeIncomeTaxesAndPreferredAndPreferenceDividendsOfSubsidiariesTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2008</td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Federal statutory rate
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>35.0</b></td>
<td nowrap="nowrap"><b>%</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">35.0</td>
<td nowrap="nowrap">%</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">35.0</td>
<td nowrap="nowrap">%</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">State income tax, net of federal deduction
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>1.8</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">2.1</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">2.6</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Employee stock plans dividend deduction
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(1.2</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(1.4</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(1.3</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Non-deductible book depreciation
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>0.8</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">0.9</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">0.8</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Difference in prior years’ deferred and current tax rate
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(0.1</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.1</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.2</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">AFUDC-Equity
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(2.2</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(2.7</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(1.9</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Production activities deduction
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.7</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.4</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">ITC basis difference
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(0.4</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Leveraged lease termination
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.9</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">MC Asset Recovery
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">2.7</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Donations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.4</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Other
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(0.2</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(0.1</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(1.0</td>
<td nowrap="nowrap">)</td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Effective income tax rate
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>33.5</b></td>
<td nowrap="nowrap"><b>%</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">34.4</td>
<td nowrap="nowrap">%</td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">33.6</td>
<td nowrap="nowrap">%</td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringApplicable U.S. federal statutory rate to earnings before income taxes and preferred and preference dividends of subsidiaries.No authoritative reference available.falsefalse
6false0us-gaap_SummaryOfIncomeTaxContingenciesTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table4 - us-gaap:SummaryOfIncomeTaxContingenciesTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2008</td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="11"><i>(in millions)</i></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Unrecognized tax benefits at beginning of year
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>199</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">146</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">264</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Tax positions from current periods
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>62</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">53</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">49</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Tax positions increase from prior periods
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>62</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">12</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">130</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Tax positions decrease from prior periods
</div></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right"><b>(27</b></td>
<td nowrap="nowrap"><b>)</b></td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(10</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Reductions due to settlements
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(297</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Reductions due to expired statute of limitations
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Balance at end of year
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>296</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">199</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">146</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringThe disclosure required for tax positions taken in the tax returns filed or to be filed for which it is more likely than not that the tax position will not be sustained upon examination by taxing authorities (i.e., uncertain tax positions) and other types of income tax contingencies, including: (1) the policy on classification of interest and penalties; (2) a tabular reconciliation of the total amounts of unrecognized tax benefits at the beginning and end of the period; the total amount(s) of: (3) unrecognized tax benefits that, if recognized, would affect the effective tax rate, and (4) interest and penalties recognized in each of the income statement and balance sheet; (5) for positions for which it is reasonably possible that the total amounts unrecognized will significantly change within 12 months of the reporting date the: (i) nature of the uncertainty, (ii) nature of the event that could occur that would cause the change, and (iii) an estimate of the range of the reasonably possible change or a statement that an estimate of the range cannot be made; and (6) a description of tax years that remain subject to examination by major tax jurisdictions.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 48
-Paragraph 21
falsefalse
7false0so_ImpactOnEffectiveTaxRateTextBlocksofalsenadurationImpact on effective tax rate.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table5 - so:ImpactOnEffectiveTaxRateTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2008</td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="11"><i>(in millions)</i></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Tax positions impacting the effective tax rate
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>217</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">199</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">143</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Tax positions not impacting the effective tax rate
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>79</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">3</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Balance of unrecognized tax benefits
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>296</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">199</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">146</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringImpact on effective tax rate.No authoritative reference available.falsefalse
8false0so_AccruedInterestForUnrecognizedTaxBenefitsTextBlocksofalsenadurationAccrued interest for unrecognized tax benefits.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel| 1falsefalsefalse00<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note Table: SO-20101231_note5_table6 - so:AccruedInterestForUnrecognizedTaxBenefitsTextBlock-->
<div align="left" style="font-size: 10pt; font-family: 'Times New Roman',Times,serif">
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 10pt" valign="bottom">
<td style="border-bottom: 1px solid #000000"> </td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2009</td>
<td style="border-bottom: 1px solid #000000"> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000">2008</td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="11"><i>(in millions)</i></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Interest accrued at beginning of year
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>21</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">15</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">31</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Interest reclassified due to settlements
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>—</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="right"> </td>
<td align="right">(49</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Interest accrued during the year
</div></td>
<td> </td>
<td> </td>
<td align="right"><b>8</b></td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">6</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">33</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 1px solid #000000"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Balance at end of year
</div></td>
<td> </td>
<td align="right"><b>$</b></td>
<td align="right"><b>29</b></td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">21</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">15</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td colspan="13" align="left" style="border-top: 3px double #000000"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Notefalsefalsefalsefalsefalse | Otherus-types:textBlockItemTypestringAccrued interest for unrecognized tax benefits.No authoritative reference available.falsefalse
17Income Taxes (Tables)UnKnownUnKnownUnKnownUnKnownfalsetrue