The increase (decrease) during the reporting period in asbestos and environmental claims reserve, net of reinsurance recoveries.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b),(c)
-URI http://asc.fasb.org/extlink&oid=65670824&loc=d3e14764-158437

Name:	us-gaap_LiabilityForAsbestosAndEnvironmentalClaimsNetPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

Insurance Claim Reserves (details) - Asbestos and Environmental Reserves - Business Insurance [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Asbestos reserves [Member]
Liability for claims and claim adjustment expense
Increase to reserves	$ 225	$ 225	$ 225	$ 225
Environmental reserves [Member]
Liability for claims and claim adjustment expense
Increase to reserves			$ 65	$ 82