Retirement Plans (Details 2) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Non-qualified Plan [Member]
Underfunded Accumulated Benefit Obligation [Abstract]
Accumulated benefit obligation	379,000,000	302,000,000
Pension [Member]
Underfunded Accumulated Benefit Obligation [Abstract]
Projected benefit obligation	388,000,000	308,000,000
Accumulated benefit obligation	379,000,000	302,000,000
Fair value of plan assets	0	0
Underfunded accumulated benefit obligation	(379,000,000)	(302,000,000)
Accumulated Benefit Obligation [Abstract]
Accumulated benefit obligation	3,900,000,000	3,200,000,000
Weighted-Average Actuarial Assumptions Used To Determine Benefit Obligations [Abstract]
Discount rate - benefit obligations	3.94%	4.72%
Compensation increase - benefit obligations	4.00%	4.00%
OPEB [Member]
Weighted-Average Actuarial Assumptions Used To Determine Benefit Obligations [Abstract]
Discount rate - benefit obligations	3.74%	4.47%
Health care cost trend rate (employees under 65)	6.34%	6.49%
Ultimate health care cost trend rate	4.50%	4.50%	4.50%
Year ultimate trend rate reached	2028	2028	2028

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The assumed health care cost trend rate used to measure the expected cost of benefits covered by the plan (gross eligible charges) for employees under age 65. 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.

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- Definition

If aggregate disclosures are presented, the aggregate underfunded accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

No definition available.

+ Details

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- Definition

For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

-URI http://asc.fasb.org/extlink&oid=6503844

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

The interest rate used to adjust for the time value of money for the plan.

+ 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 (k)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ 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 (k)(2)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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- Definition

If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 55

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=34716465&loc=d3e4179-114921

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2417-114920

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- Definition

If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

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- Definition

If aggregate disclosures are presented, the aggregate projected benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References

+ Details

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- Definition

The ultimate trend rate for health care costs.

+ 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=35743120&loc=d3e1928-114920

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- Definition

Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ 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=35743120&loc=d3e1928-114920

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