Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows provided by (used in) operating activities:
Net income (loss)	$ (33.8)	$ (1.0)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:
Amortization and depreciation	4.3	5.9
Share-based payments expense	1.5	3.2
Deferred income tax benefit, net	(5.9)	9.3
Net investment and other (gains) losses	17.9	34.5
Undistributed earnings from alternative investment portfolio	0.2	(13.6)
Change in:
Accrued investment income	(0.3)	(1.2)
Receivables	613.8	43.9
Deferred acquisition costs	(6.5)	(6.5)
Ceded unearned premiums	(50.0)	(2.9)
Reserves for losses and loss adjustment expenses	(367.2)	101.4
Unearned premiums	(3.9)	(38.5)
Ceded reinsurance payable and funds held	(60.8)	(147.8)
Income taxes	(3.0)	3.2
Accrued underwriting expenses and other liabilities	(25.1)	11.5
Other, net	(42.1)	(29.3)
Cash provided by (used in) operating activities	39.1	(27.9)
Cash flows provided by (used in) investing activities:
Sales of fixed maturity investments	0.6	291.1
Maturities and mandatory calls of fixed maturity investments	32.5	144.3
Sales of equity securities	6.0	9.0
Sales of other investments	1.9	20.9
Purchases of fixed maturity investments	(1.7)	(597.4)
Purchases of equity securities	0.0	(1.0)
Purchases of other investments	(3.9)	(17.9)
Change in foreign regulatory deposits and voluntary pools	0.0	(8.6)
Purchase of mortgage loans	0.0	(46.5)
Change in short-term investments	(215.0)	234.1
Settlements of foreign currency exchange forward contracts	5.1	0.0
Proceeds from business divestitures, net of cash transferred	54.3	22.7
Purchases of fixed assets, net	(1.4)	(0.7)
Cash provided by (used in) investing activities	(121.6)	50.0
Cash flows provided by (used in) financing activities:
Activity under stock incentive plans	0.5	(1.1)
Payment of cash dividends to preferred shareholders	(2.6)	(2.6)
Payment of cash dividends to common shareholders	0.0	(10.8)
Cash used in financing activities	(2.1)	(14.5)
Effect of exchange rate changes on cash	0.0	0.3
Net change in cash and restricted cash	(84.6)	7.9
Net change in cash balances classified as held-for-sale	70.8	0.0
Cash and restricted cash, beginning of year	50.2	146.1
Cash and restricted cash, end of period	$ 36.4	$ 154.0