Income Taxes - Components of the deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets
Unearned premium reserves	$ 742	$ 659
Pension	0	187
Accrued compensation	151	146
Discount on loss reserves	169	79
Other postretirement benefits	31	34
Net operating loss carryover	88	23
Other assets	90	91
Total deferred tax assets before valuation allowance	1,271	1,219
Valuation allowance	(24)	0
Total deferred tax assets after valuation allowance	1,247	1,219
Deferred tax liabilities
DAC	(924)	(683)
Investments	(666)	(216)
Intangible assets	(219)	(86)
Unrealized net capital gains	(163)	(539)
Pension	(9)	0
Other liabilities	(99)	(77)
Total deferred tax liabilities	(2,080)	(1,601)
Net deferred tax liabilities	$ (833)	$ (382)