Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Benefits [Abstract]
Pension Contributions	$ 0	$ 0	$ 0	$ 26
Contribution to health reimbursement account - sick time		58.00%
Contribution to health reimbursement account - earned time off		100.00%
OtherPostretirementDefinedBenefitPlanLiabilityCurrent		2	2
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year		20
Net actuarial loss portion of amortization from AOCL for pension benefits		17
Net Actuarial Loss Portion of Amortization from AOCL for Non-qualified benefits		1
Net actuarial loss portion of amortiztion of AOCL for other postretirement benefits		1
Prior service cost portion of amortization of AOCL for other postretirement benefits		1
Defined benefit plan, current annual rate of health care cost increase		7.50%	8.00%	8.00%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year		0.50%	0.50%	0.50%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate		5.00%	5.00%	5.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components		0
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation		0
Company match pre 2009 hire		6.00%
Company match post 2008 hire		5.00%
Company contribution percentage to 401k for post 2008 hires		5.00%
Company contribution percent to 401k for bargaining employees		1.00%
401k Plan Company contributions		$ 16	$ 16	$ 16

401k Plan, Company contributions during the year.

No definition available.

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- Definition

Company contribution percentage of participating employee's base salary for employees hired post January 31, 2009, regardless of whether the employee contributes to the 401k plan.

+ References

No definition available.

+ Details

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- Definition

For bargaining employees, who are subject to the International Brotherhood of Electrical Workers Local 125 agreements, the Company contributes a stated amount per compensable hour plus this percentage of the employee’s base salary, whether or not the employee contributes to the 401k Plan.

+ References

No definition available.

+ Details

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- Definition

Company match, percentage of participating employee's base salary for employees hired post January 31, 2009.

+ References

No definition available.

+ Details

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- Definition

Company match, percentage of participating employee's base salary for employees hired pre February 1, 2009.

+ References

No definition available.

+ Details

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- Definition

Contributions to the HRAs provide for claims by retirees for qualified medical costs. For active bargaining employees, the participants’ accounts are credited with 100% of their earned time off accumulated at the time of retirement.

+ References

No definition available.

+ Details

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- Definition

Contributions to the HRAs provide for claims by retirees for qualified medical costs. For active bargaining employees, the participants’ accounts are credited with 58% of the value of the employee’s accumulated sick time as of April 30, 2004.

+ References

No definition available.

+ Details

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- Definition

The assumed health care cost trend rate for the current year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

No definition available.

+ Details

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- Details

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- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, consisting of the net actuarial loss for non-qualified benefits.

+ References

No definition available.

+ Details

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- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented related to the net actuarial loss for pension benefits.

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

+ Details

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- Definition

This represents the current liability recognized in the balance sheet that is associated with other postretirement defined benefit plans (excluding pension plans).

+ References

No definition available.

+ Details

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- Definition

+ References

No definition available.

+ Details

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- Definition

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

+ References

No definition available.

+ Details

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

+ Details

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- Definition

The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

+ References

+ Details

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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (l)

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Health Care Cost Trend Rate

-URI http://asc.fasb.org/extlink&oid=6514820

+ Details

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- Definition

The ultimate trend rate for health care costs.

+ References

+ Details

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- Definition

The amount of cash or cash equivalents contributed by the entity to fund its pension plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

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