Benefits 1 (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	3 Months Ended												6 Months Ended		3 Months Ended				6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Successor [Member] Pension Benefits [Member]		Jun. 30, 2012 Successor [Member] Pension Benefits [Member]		Jun. 30, 2012 Successor [Member] Other Postretirement Benefits [Member]		Jun. 30, 2012 Successor [Member] Other Postretirement Benefits [Member]		Mar. 25, 2012 Predecessor [Member] Pension Benefits [Member]		Jun. 30, 2011 Predecessor [Member] Pension Benefits [Member]		Jun. 30, 2011 Predecessor [Member] Pension Benefits [Member]		Mar. 25, 2012 Predecessor [Member] Other Postretirement Benefits [Member]		Jun. 30, 2011 Predecessor [Member] Other Postretirement Benefits [Member]		Jun. 30, 2011 Predecessor [Member] Other Postretirement Benefits [Member]
Net Periodic Benefit Cost:
Service cost		$ 2,083		$ 2,177		$ 206		$ 223		$ 998		$ 935		$ 1,870		$ 881		$ 881		$ 1,761
Interest cost		(1,651)		(1,462)		611		662		2,095		2,525		5,050		1,254		1,446		2,892
Expected return on plan assets		(756)		(1,005)		(1,623)		(1,758)		(2,461)		(2,647)		(5,293)		(1,367)		(1,450)		(2,899)
Prior service cost (credit) amortization		0		0		0		0		133		147		294		(409)		(453)		(906)
Actuarial loss (gain) amortization		172		172		0		0		2,308		1,984		3,967		273		(403)		(806)
Curtailment recognition	15,300			0	[1]			(15,332)	[1]	0	[1]			0	[1]	0	[1]			0	[1]
Net periodic benefit cost subtotal		(152)		(118)		(806)		(16,205)		3,073		2,944		5,888		632		21		42
Regulatory adjustment		493	[2]	497	[2]	666	[2]	675	[2]	253	[2]	191	[2]	383	[2]	657	[2]	666	[2]	1,332	[2]
Net periodic benefit cost		$ 341		$ 379		$ (140)		$ (15,530)		$ 3,326		$ 3,135		$ 6,271		$ 1,289		$ 687		$ 1,374

[1] Subsequent to the Merger, the Company amended certain of its other postretirement employee benefit plans, which prospectively restrict participation in the plans for the impacted active employees. The plan amendments resulted in the plans becoming currently over-funded and, accordingly, the Company recorded a pre-tax curtailment gain of $74.6 million. Such gain was offset by establishment of a non-current refund liability in the amount of $59.3 million. As such, the net curtailment gain recognition was $15.3 million.

[2] In the Distribution segment, the Company recovers certain qualified pension benefit plan and other postretirement benefit plan costs through rates charged to utility customers. Certain utility commissions require that the recovery of these costs be based on the Employee Retirement Income Security Act of 1974, as amended, or other utility commission specific guidelines. The difference between these regulatory-based amounts and the periodic benefit cost calculated pursuant to GAAP is deferred as a regulatory asset or liability and amortized to expense over periods in which this difference will be recovered in rates, as promulgated by the applicable utility commission.