| **Benefit Plans (Tables)**                            | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| **Compensation and Retirement Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Components of net periodic cost (benefit)             | Net Periodic Cost (Benefit)Periods ended June 30Three Months Six Months(In millions)2014 2013 2014 2013Pension benefit       Service cost$1 $3 $4 $6Interest cost on projected benefit obligation33 30 66 60Expected return on plan assets(48) (45) (96) (90)Amortization of net actuarial loss7 12 13 24Net periodic pension benefit$(7) $— $(13) $—        Postretirement benefit       Interest cost on projected benefit obligation$1 $1 $1 $1Amortization of prior service credit(5) (5) (9) (9)Curtailment gain (86)—(86)—Net periodic postretirement benefit$(90) $(4) $(94) $(8) |

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| - Details**Name:**us-gaap_CompensationAndRetirementDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
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| - Definition
Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.
+ 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 (h) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920
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