Income Taxes (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred tax liabilities:
Net deferred income tax asset	$ 37	$ 2
Net deferred income tax liability	(490)	(450)
Net deferred income tax asset (liability) - consolidated	(453)	(448)
Indemnity
Deferred tax assets:
Other employee benefits	18	14
Pension and other postretirement benefits	55	24
Other	4	3
Total deferred tax assets	77	41
Deferred tax liabilities:
Unrealized gains on investments	4	3
Limited partnerships	11	11
Depreciation	17	17
Prepaid expenses	8	7
Other	0	1
Total deferred tax liabilities	40	39
Net deferred income tax asset	37	2
Net deferred income tax liability	0	0
Exchange
Deferred tax assets:
Loss reserve discount	55	63
Unearned premiums	214	197
Write-downs of impaired securities	8	18
Other	25	19
Total deferred tax assets	302	297
Deferred tax liabilities:
Deferred policy acquisition costs	191	185
Unrealized gains on investments	510	489
Limited partnerships	67	61
Other	24	12
Total deferred tax liabilities	792	747
Net deferred income tax asset	0	0
Net deferred income tax liability	$ (490)	$ (450)