Postretirement Benefits Pension Benefits (Components of Postretirement Benefit Expense) (Details) $ in Millions	12 Months Ended
Dec. 31, 2014 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Curtailments	$ (7)

The amount of decrease that is related to an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(10)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Plan Curtailment
-URI http://asc.fasb.org/extlink&oid=6520938

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 30
-Section 15
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=7577095&loc=d3e8001-114927

Name:	us-gaap_DefinedBenefitPlanCurtailments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration