Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Average Annual Percentage Payout Of Incurred Claims By Age Net Of Reinsurance) (Details) - Property and Casualty Insurance [Member]	Dec. 31, 2017
Average annual Percentage Payout [Abstract]
Year 1	56.60%
Year 2	20.80%
Year 3	11.20%
Year 4	3.50%
Year 5	2.40%
Year 6	0.00%

Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Average Annual Percentage Payout Of Incurred Claims By Age Net Of Reinsurance) (Details) - Property and Casualty Insurance [Member]

Dec. 31, 2017

Average annual Percentage Payout [Abstract]

56.60%

20.80%

11.20%

3.50%

2.40%

0.00%