Retirement Plans (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
OPEB [Member]
Cash Contributions [Abstract]
Cash contribution to non-qualified OPEB plan	$ 25	$ 23
Pension Qualified Plan [Member]
Cash Contributions [Abstract]
Cash contributions to qualified pension plan	200	200
Pension Non-qualified Plan [Member]
Cash Contributions [Abstract]
Cash contributions to non-qualified pension plan	$ 33	$ 16

The amount of contributions made by the employer that were non-qualified.

No definition available.

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- Definition

The increase in the fair value of plan assets from contributions made by the employer.

+ 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 (b)(3)

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

+ Details

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- Definition

The amount of cash or cash equivalents contributed during the reporting period by the entity to fund non-pension postretirement benefits.

+ 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

+ Details

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- Details

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- Details

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