Reinsurance (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Funds held under reinsurance agreements, liability	$ 3,400,000,000	$ 3,900,000,000
Reinsurance recoveries reported in insurance claims and policyholders' benefits reported on the Consolidated Statement of Operations	1,379,000,000	1,450,000,000	1,443,000,000
Subsidiaries of Berkshire Hathaway Group [Member]
Largest Recoverables From Single Reinsurer	2,565,000,000
Subsidiaries of Hartford Insurance Group [Member]
Largest Recoverables From Single Reinsurer	244,000,000
Subsidiaries of Wilton Re [Member]
Largest Recoverables From Single Reinsurer	185,000,000
Significant Captive Program [Member]
Direct and ceded earned premiums	2,643,000,000	2,156,000,000	1,794,000,000
Reinsurance recoveries reported in insurance claims and policyholders' benefits reported on the Consolidated Statement of Operations	$ 1,458,000,000	$ 712,000,000	$ 814,000,000