Claim and Claim Adjustment Expense Reserves (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Claim and Claim Adjustment Expense Reserves [Abstract]
Catastrophe losses net of reinsurance	$ 17	$ 42	$ 147	$ 146
Net prior year claim and claim adjustment expense reserve development, Workers' Compensation Reinsurance Pool	$ (26)		$ (26)