Employee Benefit Plans - Employer Contributions (Details) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012 Domestic Pension Plans [Member] USD ($)	Sep. 30, 2012 Domestic Other Postretirement Plans [Member] USD ($)	Sep. 30, 2012 UK Pension Plan [Member] USD ($)	Sep. 30, 2012 UK Pension Plan [Member] GBP (£)
Defined Benefit Plan Disclosure [Line Items]
Estimated employer contributions for 2012	$ 114	$ 9		£ 50
Employer contributions	$ 111	$ 4	$ 59	£ 38

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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=21915506&loc=d3e1928-114920

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