Retirement Plans (Details 13) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net actuarial gain:
Reclassified to earnings from equity	$ (1)
Gains in current year	(2)
Net actuarial gain, pretax	$ (3)

Before tax amount of the (increase) decrease in the value of the projected benefit obligation and the increase (decrease) in the value of the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption that has not been recognized in net periodic benefit cost.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=20435746&loc=d3e637-108580

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 10A

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=20435746&loc=SL7669646-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration