Income Taxes - Significant components of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Federal net operating loss carryforwards	$ 23	$ 27
Foreign underwriting losses	93	80
Capital loss carryforwards	0	32
Insurance claims and reserves	743	694
Employee benefits	88	84
Other, net	44	45
Total deferred tax assets before valuation allowance	991	962
Valuation allowance against deferred tax assets	(119)	(109)
Total deferred tax assets	872	853
Deferred tax liabilities:
Investment securities	(70)	(341)
Deferred policy acquisition costs	(291)	(202)
Insurance claims and reserves transition liability	(110)	(128)
Real estate, property and equipment	(36)	(35)
Total deferred tax liabilities	(507)	(706)
Net deferred tax asset (liability)	365	147
Excluding Unrealized Gains
Deferred tax assets:
Federal net operating loss carryforwards	23	27
Foreign underwriting losses	93	80
Capital loss carryforwards	0	32
Insurance claims and reserves	740	665
Employee benefits	88	84
Other, net	44	48
Total deferred tax assets before valuation allowance	988	936
Valuation allowance against deferred tax assets	(119)	(109)
Total deferred tax assets	869	827
Deferred tax liabilities:
Investment securities	(36)	(1)
Deferred policy acquisition costs	(300)	(293)
Insurance claims and reserves transition liability	(110)	(128)
Real estate, property and equipment	(36)	(35)
Total deferred tax liabilities	(482)	(457)
Net deferred tax asset (liability)	387	370
Impact of Unrealized Gains
Deferred tax assets:
Federal net operating loss carryforwards	0	0
Foreign underwriting losses	0	0
Capital loss carryforwards	0	0
Insurance claims and reserves	3	29
Employee benefits	0	0
Other, net	0	(3)
Total deferred tax assets before valuation allowance	3	26
Valuation allowance against deferred tax assets	0	0
Total deferred tax assets	3	26
Deferred tax liabilities:
Investment securities	(34)	(340)
Deferred policy acquisition costs	9	91
Insurance claims and reserves transition liability	0	0
Real estate, property and equipment	0	0
Total deferred tax liabilities	(25)	(249)
Net deferred tax asset (liability)	$ (22)	$ (223)