Employee Benefit Plans Employee Benefit Plans Narrative (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions for 2013	$ 64
Contributions by employer	62
Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions for 2013	13
Contributions by employer	$ 4

Amount of the employer's best estimate of contributions expected to be paid to the plan in the current fiscal period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2709-114920

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