Derivative Instrument and Hedging Activities 1 Narrative (Details) (USD $)															6 Months Ended						6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Term Loan Due March 2012 [Member]	Jun. 30, 2012 Successor [Member]	Jun. 30, 2012 Successor [Member] Southern Union [Member]	Jun. 30, 2012 Successor [Member] Southern Union [Member] Junior Subordinated Debt [Member]		Dec. 31, 2011 Successor [Member] Southern Union [Member] Junior Subordinated Debt [Member]		Jun. 30, 2012 LIBOR [Member] Southern Union [Member] Junior Subordinated Debt [Member]	Jun. 30, 2012 Interest Rate Swap [Member]	Dec. 31, 2011 Interest Rate Swap [Member]	Dec. 31, 2011 Interest Rate Swap [Member] Interest Rate Swap, Ten Year Period [Member]	Dec. 31, 2011 Interest Rate Swap [Member] Interest Rate Swap, Five Year Period [Member]	Jun. 30, 2012 Interest Rate Swap [Member] LIBOR [Member] Junior Subordinated Debt [Member]	Jun. 30, 2012 Natural gas price swaps [Member] Gathering and Processing [Member]	Jun. 30, 2012 Natural gas price swaps [Member] Year 2012 [Member] Gathering and Processing [Member] MMbtu	Jun. 30, 2012 Natural gas price swaps [Member] Year 2012 [Member] MMBtus [Member] Gathering and Processing [Member] MMbtu	Jun. 30, 2012 Natural gas price swaps [Member] Year 2013 [Member] Gathering and Processing [Member] MMbtu	Jun. 30, 2012 Natural gas price swaps [Member] Year 2013 [Member] MMBtus [Member] Gathering and Processing [Member] MMbtu	Jun. 30, 2012 Natural gas price swaps [Member] Year 2014 [Member] Gathering and Processing [Member] MMbtu	Jun. 30, 2012 NGL price swaps [Member] Gathering and Processing [Member]	Jun. 30, 2012 NGL price swaps [Member] Gallons [Member] Gathering and Processing [Member] gal	Jun. 30, 2012 NGL price swaps [Member] MMBtus [Member] Gathering and Processing [Member] MMbtu
Derivative [Line Items]
Long-term debt			$ 3,112,536,000	$ 1,340,543,000	$ 600,000,000	[1]	$ 600,000,000	[1]
Derivative notional amount										455,000,000	525,000,000	450,000,000	75,000,000
Debt instrument, three month LIBOR, basis spread on variable rate									3.0175%					3.0175%
Interest rate swap, period (in years)												10 years	5 years
Derivative fixed interest rate										3.63%
Derivative notional amount, nonmonetary (in MMBtu or gallons)																7,290,000	5,520,000	10,770,000	10,037,500	1,690,000		32,898,096	2,760,000
Debt, face amount		455,000,000
Net, after-tax losses in accumulated other comprehensive income															8,000,000						9,100,000
Derivative net liability position, aggregate fair value	$ 10,000,000

[1] Effective November 1, 2011, the interest rate on the Junior Subordinated Notes changed to a variable rate based upon the three-month LIBOR rate plus 3.0175%, reset quarterly. See Interest Rate Swaps below for more information regarding the interest rate on these notes.