Insurance Claim Reserves (details) - Asbestos and Environmental Reserves (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Asbestos reserves [Member]
Asbestos and environmental reserves
Increase (decrease) to asbestos and environmental reserves	$ 175	$ 140	$ 185
Net losses paid	284	350	341
Asbestos reserves [Member] \| Business Insurance [Member]
Asbestos and environmental reserves
Increase (decrease) to asbestos and environmental reserves	175	140	185
Environmental reserves [Member]
Asbestos and environmental reserves
Increase (decrease) to asbestos and environmental reserves	76	35	70
Environmental reserves [Member] \| Business Insurance [Member]
Asbestos and environmental reserves
Increase (decrease) to asbestos and environmental reserves	$ 76	$ 35	$ 70

Amount of asbestos claims paid in the current period, net of reinsurance recoveries.

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

-Publisher AICPA

-Name Audit and Accounting Guide (AAG)

-Number AAG-PLI

-Chapter 4

-Paragraph 132, 133, 135, 136, 137

-IssueDate 2006-09-01

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 AICPA

-Name Statement of Position (SOP)

-Number 94-5

-Paragraph 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 40

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437

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