Reinsurance (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Property-liability insurance claims and claims expense
Reductions to costs and expenses due to reinsurance ceded amounts
Ceded losses incurred	$ 229	$ 120	$ 334	$ 218
Life and annuity contract benefits
Reductions to costs and expenses due to reinsurance ceded amounts
Ceded losses incurred	50	79	127	205
Interest credited to contractholder funds
Reductions to costs and expenses due to reinsurance ceded amounts
Ceded losses incurred	7	9	13	15
Property-liability insurance premiums earned
Reductions to premiums and contract charges due to reinsurance premium ceded amounts
Property-liability insurance premiums earned	251	262	511	520
Life and annuity premiums and contract charges
Reductions to premiums and contract charges due to reinsurance premium ceded amounts
Life and annuity premiums and contract charges	$ 85	$ 84	$ 170	$ 237