Income Taxes - Deferred tax assets (liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets
Loss reserves and tax discount	$ 214	$ 150
Unearned premium reserve and other underwriting related reserves	385	355
Investment-related items	130	183
Employee benefits	287	287
Net operating loss carryover	84	521
Other	27	1
Total Deferred Tax Assets	1,127	1,497
Deferred Tax Assets, Valuation Allowance	(4)	0
Deferred Tax Assets, Net of Valuation Allowance	1,123	1,497
Deferred Tax Liabilities
Deferred acquisition costs	(143)	(104)
Net unrealized gains on investments	(458)	(7)
Other depreciable and amortizable assets	(223)	(135)
Other	0	(3)
Total Deferred Tax Liabilities	(824)	(249)
Net Deferred Tax Asset	$ 299	$ 1,248