Amount of increase over the base rate sought by a regulated company in a rate case filing

Amount of recovery sought in a rate case filing for earnings share adjustment

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The percent of customers that are attributable to residential and small general service customers

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The percent of net operating revenues that are attributable to residential and small general service customers

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Data Type:	xbrli:integerItemType
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Amount the Company is requesting as the appropriate amount for recovery of a prior year.

Amount of increase in revenues authorized by a regulatory authority

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

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Data Type:	xbrli:decimalItemType
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Amount of regulatory costs not yet approved by the regulatory authority.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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Regulation and Rates (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	9 Months Ended			0 Months Ended		1 Months Ended	0 Months Ended
	Dec. 13, 2010 Panhandle [Member]	Sep. 30, 2011 Panhandle [Member]	Aug. 31, 2011 Panhandle [Member]	Aug. 31, 2009 Panhandle [Member]	Feb. 10, 2010 Missouri Gas Energy [Member]	Apr. 02, 2009 Missouri Gas Energy [Member]	Feb. 28, 2010 Missouri Gas Energy [Member]	Jul. 13, 2011 New England Gas Company [Member]	Sep. 15, 2008 New England Gas Company [Member]
Regulated Operations [Abstract]
Amount Of Regulatory Costs Not Yet Approved			$ 47	$ 38
Surcharge Recovery Period	21.4
Base Rate Increase						32.4
Refunds Reserved		17.7
Revenue Increase Authorized					16.2
Percent Residential Small General Service Customers							99
Percent Residential Small General Service Net Operating Revenues							91
Earnings Share Adjustment Recovery								1.7	4.0
Remand Recovery								$ 4.1