Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012 Successor [Member]	Dec. 31, 2011 Predecessor [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] Distribution Plant [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] Gathering and processing plant [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] Transmission plant [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] General plant - LNG [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] Underground storage plant [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] General plant and other [Member]	Dec. 31, 2012 Regulated Operation [Member] Successor [Member] Construction in Progress [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] Distribution Plant [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] Gathering and processing plant [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] Transmission plant [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] General plant - LNG [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] Underground storage plant [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] General plant and other [Member]	Dec. 31, 2011 Regulated Operation [Member] Predecessor [Member] Construction in Progress [Member]	Dec. 31, 2012 Unregulated Operation [Member] Successor [Member]	Dec. 31, 2012 Unregulated Operation [Member] Successor [Member] Distribution Plant [Member]	Dec. 31, 2012 Unregulated Operation [Member] Successor [Member] Gathering and processing plant [Member]	Dec. 31, 2012 Unregulated Operation [Member] Successor [Member] General plant and other [Member]	Dec. 31, 2012 Unregulated Operation [Member] Successor [Member] Construction in Progress [Member]	Dec. 31, 2011 Unregulated Operation [Member] Predecessor [Member]	Dec. 31, 2011 Unregulated Operation [Member] Predecessor [Member] Distribution Plant [Member]	Dec. 31, 2011 Unregulated Operation [Member] Predecessor [Member] Gathering and processing plant [Member]	Dec. 31, 2011 Unregulated Operation [Member] Predecessor [Member] General plant and other [Member]	Dec. 31, 2011 Unregulated Operation [Member] Predecessor [Member] Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 5,763	$ 7,300	$ 4,170	$ 0	$ 163	$ 2,580	$ 966	$ 306	$ 110	$ 45	$ 5,324	$ 1,043	$ 167	$ 2,321	$ 1,119	$ 322	$ 304	$ 48	$ 1,593	$ 60	$ 1,296	$ 10	$ 227	$ 1,976	$ 60	$ 1,840	$ 20	$ 56
Less: Accumulated depreciation and Amortization	105	1,573	58								1,219								47					354
Property, Plant and Equipment, Net	$ 5,658	$ 5,727	$ 4,112								$ 4,105								$ 1,546					$ 1,622