Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

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

The amounts in accumulated other comprehensive loss expected to be recognized as components of net periodic benefit cost during 2013 are as follows:

	Postretirement Benefits
	(in millions)
Unrecognized actuarial loss	$	1
Unrecognized prior service cost	1
Amounts in accumulated other comprehensive loss to be recognized as net periodic cost	$	2

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

The following benefit payments are expected to be made by the postretirement benefit plan:

	Postretirement Benefit Plan
	Benefit Payments		Medicare Subsidy Receipts
	(in millions)
2013	$	11	$	(2	)
2014	11		(2		)
2015	11		(2		)
2016	12		(2		)
2017	12		(2		)
2018-2022	64		(16		)

Following are reconciliations of CERC’s beginning and ending balances of its postretirement benefit plan’s benefit obligation, plan assets and funded status for 2011 and 2012. The measurement dates for plan assets and obligations were December 31, 2011 and 2012.

	December 31,
	2011			2012
	(in millions , except for actuarial assumptions)
Change in Benefit Obligation
Accumulated benefit obligation, beginning of year	$	112		$	118
Service cost	1			1
Interest cost	6			5
Benefits paid	(14		)	(13		)
Participant contributions	4			4
Medicare reimbursement	2			2
Early retiree reinsurance program reimbursement	1			—
Actuarial loss	6			16
Accumulated benefit obligation, end of year	$	118		$	133
Change in Plan Assets
Plan assets, beginning of year	$	22		$	22
Benefits paid	(14		)	(13		)
Employer contributions	9			9
Participant contributions	4			4
Actual investment return	1			2
Plan assets, end of year	$	22		$	24
Amounts Recognized in Balance Sheets
Current liabilities-other	$	(7	)	$	(7	)
Other liabilities-benefit obligations	(89		)	(102		)
Net liability, end of year	$	(96	)	$	(109	)
Actuarial Assumptions
Discount rate	4.80		%	3.90		%
Expected long-term return on assets	3.10		%	3.10		%
Healthcare cost trend rate assumed for the next year	8.00		%	9.00		%
Prescription cost trend rate assumed for the next year	8.00		%	9.00		%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate)	5.50		%	5.50		%
Year that the healthcare rate reaches the ultimate trend rate	2017			2017
Year that the prescription drug rate reaches the ultimate trend rate	2017			2017

As part of the investment strategy discussed above, CERC adopted and maintained the following asset allocation ranges for its postretirement benefit plan:

U.S. equity	15-25%
International equity	2-12%
Fixed income	68-78%
Cash	0-2%

The net postretirement benefit cost includes the following components:

	Year Ended December 31,
	2010			2011			2012
	(in millions)
Service cost — benefits earned during the period	$	1		$	1		$	1
Interest cost on accumulated benefit obligation	7			6			5
Expected return on plan assets	(1		)	(1		)	(1		)
Amortization of prior service cost	2			2			2
Amortization of net loss	—			1			3
Net postretirement benefit cost	$	9		$	9		$	10

CERC used the following assumptions to determine net postretirement benefit costs:

	Year Ended December 31,
	2010		2011		2012
Discount rate	5.70	%	5.20	%	4.80	%
Expected return on plan assets	4.50	%	4.50	%	3.10	%

Amounts recognized in accumulated other comprehensive loss consist of the following:

	December 31,
	2011			2012
	(in millions)
Unrecognized actuarial loss	$	28		$	20
Unrecognized prior service cost	4			2
Total recognized in accumulated other comprehensive loss	32			22
Less deferred tax benefit (1)	(25		)	(21		)
Net amount recognized in accumulated other comprehensive loss	$	7		$	1

________________

(1) CERC’s postretirement benefit obligation is reduced by the impact of previously non-taxable government subsidies under the Medicare Prescription Drug Act.  Because the subsidies were non-taxable, the temporary difference used in measuring the deferred tax impact was determined on the unrecognized losses excluding such subsidies.

The changes in plan assets and benefit obligations recognized in other comprehensive income during 2012 are as follows:

	Postretirement Benefits
	(in millions)
Net loss	$	(8	)
Amortization of prior service cost	(2		)
Total recognized in other comprehensive income	$	(10	)

Defined Benefit Plan Schedule Of Effect Of One Percentage Point Change In Assumed Health Care Cost Trend Rates Text Block

Assumed healthcare cost trend rates have a significant effect on the reported amounts for CERC’s postretirement benefit plans. A 1% change in the assumed healthcare cost trend rate would have the following effects:

	1% Increase		1% Decrease
	(in millions)
Effect on the postretirement benefit obligation	$	4	$	(3	)
Effect on the total of service and interest cost	—		—

Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Text Block]

The fair values of CERC’s postretirement plan assets at December 31, 2011 and 2012, by asset category are as follows:

	Fair Value Measurements at December 31, 2011 (in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Mutual funds (1)	$	22	$	22	$	—	$	—
Total	$	22	$	22	$	—	$	—

________________

(1) 72% of the amount invested in mutual funds was in fixed income securities; 22% was in U.S. equities and 6% was in international equities.

	Fair Value Measurements at December 31, 2012 (in millions)
	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Mutual funds (1)	$	24	$	24	$	—	$	—
Total	$	24	$	24	$	—	$	—

 ________________

(1) 70% of the amount invested in mutual funds was in fixed income securities; 23% was in U.S. equities and 7% was in international equities.