Commitments, Guarantees and Contingent Liabilities (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012 employee claim	Dec. 31, 2011
Proceedings:
Reserves for asbestos claims	$ 1,030,000,000	$ 1,080,000,000
Reinsurance recoverables for asbestos claims	496,000,000	529,000,000
Reserves for environmental claims	193,000,000	185,000,000
Reinsurance recoverables for environmental claims	48,000,000	40,000,000
Percentage of net asbestos and environmental reserves that were for incurred but not reported estimated losses	58.00%	59.00%
Number of former employee agents plaintiffs seek benefits for	6,500
Number of claims asserted in Romero II	3
Number of claims barred in Romero II	2
Minimum
Proceedings:
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued	0
Maximum
Proceedings:
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued	830,000,000
Residual guarantee
Guarantees:
Maximum amount at risk pursuant to a guarantee	46,000,000
Guarantee obligations term, low end of range	1 year
Guarantee obligations term, high end of range	3 years
Guarantee on fixed income securities
Guarantees:
Maximum amount at risk pursuant to a guarantee	$ 5,000,000