Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues
Premiums	$ 1,380.0	$ 1,263.8
Net investment income	78.7	76.9
Net realized and unrealized investment gains (losses):
Net realized gains (losses) from sales and other	(1.1)	3.0
Net change in fair value of equity securities	(7.1)	(18.0)
Impairments on investments:
Credit-related impairments	(4.5)	(0.6)
Losses on intent to sell securities	(10.3)	(0.3)
Impairments on investments	(14.8)	(0.9)
Total net realized and unrealized investment losses	(23.0)	(15.9)
Fees and other income	8.0	5.9
Total revenues	1,443.7	1,330.7
Losses and expenses
Losses and loss adjustment expenses	1,017.4	787.5
Amortization of deferred acquisition costs	288.8	262.9
Interest expense	8.5	8.5
Other operating expenses	146.5	141.8
Total losses and expenses	1,461.2	1,200.7
Income (loss) from continuing operations before income taxes	(17.5)	130.0
Income tax expense (benefit):
Current	2.2	30.2
Deferred	(7.7)	(5.5)
Total income tax expense (benefit)	(5.5)	24.7
Income (loss) from continuing operations	(12.0)	105.3
Discontinued operations (net of taxes):
Net income (loss)	$ (12.0)	$ 104.9
Basic:
Income (loss) from continuing operations	$ (0.34)	$ 2.96
Net income (loss) per share	$ (0.34)	$ 2.95
Weighted average shares outstanding	35.6	35.5
Diluted:
Income (loss) from continuing operations	$ (0.34)	$ 2.91
Net income (loss) per share	$ (0.34)	$ 2.90
Weighted average shares outstanding	35.6	36.1
Life [Member]
Discontinued operations (net of taxes):
Loss from discontinued life businesses		$ (0.4)
Basic:
Loss from discontinued operations		$ (0.01)
Diluted:
Loss from discontinued life businesses		$ (0.01)