Pension and OPEB (Tables)

12 Months Ended

Dec. 31, 2011

COMPONENTS OF PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS NET PERIODIC BENEFIT COSTS: [Abstract]

Schedule of Changes in Accumulated Postemployment Benefit Obligations [Table Text Block]

	Pension Benefits						Other Postretirement Benefits
	at December 31,						at December 31,
	2011			2010			2011			2010
Change in benefit obligation:
Benefit obligation at beginning of period	$	701,152		$	654,022		$	3,257,199		$	2,844,093
Service cost	17,457			14,491			13,677			13,147
Interest cost	37,744			37,150			179,739			162,815
Actuarial loss (gain)	159,320			54,006			(51,650		)	400,118
Plan amendments	(7,186		)	682			—			204
Dominion Acquisition	—			900			—			2,800
Participant contributions	—			—			6,088			4,802
Benefits and other payments	(51,135		)	(60,099		)	(162,853		)	(170,780		)
Benefit obligation at end of period	$	857,352		$	701,152		$	3,242,200		$	3,257,199
Change in plan assets:
Fair value of plan assets at beginning of period	$	537,721		$	462,000		$	—		$	—
Actual return on plan assets	23,791			63,444			—			—
Company contributions	72,194			72,376			156,765			165,978
Participant contributions	—			—			6,088			4,802
Benefits and other payments	(51,135		)	(60,099		)	(162,853		)	(170,780		)
Fair value of plan assets at end of period	$	582,571		$	537,721		$	—		$	—
Funded status:
Current liabilities	$	(5,713	)	$	(2,258	)	$	(182,529	)	$	(179,809	)
Noncurrent liabilities	(269,069		)	(161,173		)	(3,059,671		)	(3,077,390		)
Net obligation recognized	$	(274,782	)	$	(163,431	)	$	(3,242,200	)	$	(3,257,199	)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	$	494,622		$	358,674		$	1,328,077		$	1,485,090
Prior service credit	(8,244		)	(1,725		)	(75,546		)	(121,943		)
Net amount recognized (before tax effect)	$	486,378		$	356,949		$	1,252,531		$	1,363,147

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

The components of net periodic benefit costs are as follows:

	Pension Benefits									Other Postretirement Benefits
	For the Years Ended December 31,									For the Years Ended December 31,
	2011			2010			2009			2011			2010			2009
Components of net periodic benefit cost:
Service cost	$	17,457		$	14,485		$	12,332		$	13,677		$	13,147		$	12,654
Interest cost	37,744			37,150			35,483			179,739			162,815			151,451
Expected return on plan assets	(38,522		)	(36,977		)	(36,631		)	—			—			—
Amortization of prior service cost (credits)	(666		)	(735		)	(1,109		)	(46,397		)	(46,415		)	(46,415		)
Recognized net actuarial loss	38,102			31,870			22,263			105,364			70,145			50,357
Benefit cost	$	54,115		$	45,793		$	32,338		$	252,383		$	199,692		$	168,047

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block]

				Other
	Pension			Postretirement
	Benefits			Benefits
Prior Service cost (benefit) recognition	$	(1,630	)	$	(46,397	)
Actuarial loss recognition	$	49,049		$	81,380

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]

	As of December 31,
	2011		2010
Projected benefit obligation	$	857,352	$	701,152
Accumulated benefit obligation	$	782,820	$	629,433
Fair value of plan assets	$	582,571	$	537,721

Schedule of Assumptions Used [Table Text Block]

The weighted-average assumptions used to determine benefit obligations are as follows:

	Pension Benefits				Other Postretirement Benefits
	For the Year Ended				For the Year Ended
	December 31,				December 31,
	2011		2010		2011		2010
Discount rate	4.50	%	5.30	%	4.51	%	5.33	%
Rate of compensation increase	3.77	%	3.68	%	—		—

The weighted-average assumptions used to determine net periodic benefit costs are as follows:

	Pension Benefits at						Other Postretirement Benefits at
	December 31,						December 31,
	2011		2010		2009		2011		2010		2009
Discount rate	5.30	%	5.79	%	6.28	%	5.33	%	5.87	%	6.20	%
Expected long-term return on plan assets	8.00	%	8.00	%	8.00	%	—		—		—
Rate of compensation increase	3.66	%	4.14	%	4.05	%	—		—		—

Schedule of Health Care Cost Trend Rates [Table Text Block]

The assumed health care cost trend rates are as follows:

	At December 31,
	2011		2010		2009
Health care cost trend rate for next year	6.85	%	8.47	%	8.74	%
Rate to which the cost trend is assumed to decline (ultimate trend rate)	4.50	%	4.50	%	4.50	%
Year that the rate reaches ultimate trend rate	2026		2023		2023

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]

Assumed health care cost trend rates have a significant effect on the amounts reported for the medical plans. A one-percentage point change in assumed health care cost trend rates would have the following effects:

	1-Percentage		1-Percentage
	Point Increase		Point Decrease
Effect on total of service and interest cost components	$	24,909	$	(20,876	)
Effect on accumulated postretirement benefit obligation	$	410,191	$	(349,038	)

Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block]

Assumed discount rates also have a significant effect on the amounts reported for both pension and other benefit costs. A one-quarter percentage point change in assumed discount rate would have the following effect on benefit costs:

	0.25 Percentage			0.25 Percentage
	Point Increase			Point Decrease
Pension benefit costs (decrease) increase	$	(1,948	)	$	1,965
Other postemployment benefits costs (decrease) increase	$	(4,666	)	$	5,543

Schedule of Allocation of Plan Assets [Table Text Block]

The fair values of plan assets at December 31, 2011 and 2010 by asset category are as follows:

	Fair Value Measurements at December 31, 2011								Fair Value Measurements at December 31, 2010
			Quoted								Quoted
			Prices in								Prices in
			Active								Active
			Markets for		Significant		Significant				Markets for		Significant		Significant
			Identical		Observable		Unobservable				Identical		Observable		Unobservable
			Assets		Inputs		Inputs				Assets		Inputs		Inputs
	Total		(Level 1)		(Level 2)		(Level 3)		Total		(Level 1)		(Level 2)		(Level 3)
Asset Category
Cash/Accrued Income	$	552	$	552	$	—	$	—	$	482	$	482	$	—	$	—
US Equities (a)	11		11		—		—		2		2		—		—
MGI Collective Trusts
US Large Cap Growth Equity (b)	46,670		—		46,670		—		48,328		—		48,328		—
US Large Cap Value Equity (c)	48,115		—		48,115		—		48,802		—		48,802		—
US Small/Mid Cap Growth Equity (d)	20,897		—		20,897		—		20,580		—		20,580		—
US Small/Mid Cap Value Equity (e)	21,375		—		21,375		—		20,459		—		20,459		—
US Core Fixed Income (f)	29,881		—		29,881		—		27,660		—		27,660		—
Non-US Core Equity (g)	139,395		—		139,395		—		130,305		—		130,305		—
US Long Duration Investment Grade Fixed Income (h)	35,709		—		35,709		—		46,848		—		46,848		—
US Long Duration Fixed Income (i)	34,434		—		34,434		—		67,949		—		67,949		—
US Large Cap Passive Equity (j)	71,786		—		71,786		—		59,776		—		59,776		—
US Passive Fixed Income (k)	16,158		—		16,158		—		14,996		—		14,996		—
US Long Duration Passive Fixed Income (l)	21,422		—		21,422		—		26,796		—		26,796		—
US Ultra Long Duration Fixed Income (m)	33,466		—		33,466		—		24,738		—		24,738		—
US Active Long Corporate Investment (n)	62,700		—		62,700		—		—		—		—		—
Total	$	582,571	$	563	$	582,008	$	—	$	537,721	$	484	$	537,237	$	—

Schedule of Expected Benefit Payments [Table Text Block]

The following benefit payments, reflecting expected future service, are expected to be paid: