Insurance Claim Reserves (details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Insurance Claim Reserves disclosure
Amount of decrease in gross claims and claim adjustment expense reserves	$ 1,040,000,000	$ 23,000,000
Amount of decline in reinsurance recoverables on unpaid losses	492,000,000	974,000,000
Accretion of discount	50,000,000	48,000,000	48,000,000
Asbestos and environmental claims reserves, balance	$ 2,700,000,000	$ 2,690,000,000