Consolidated statements of stockholders' equity or deficit - amounts - USD ($) $ in Millions	Total	Cumulative effect adjustment	MCPS including paid-in capital	Common stock including paid-in capital	Accumulated (deficit) earnings	Accumulated (deficit) earnings Cumulative effect adjustment	AOCI
Beginning balance at Dec. 31, 2019	$ 2,462.2		$ 1,003.7	$ 1,748.1	$ (203.7)		$ (85.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	224.2				116.6		107.6
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	42.2			42.2
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings	64.6			(64.6)
Exercise of stock options	11.9			11.9
Ending balance at Dec. 31, 2020	2,674.3	$ (1.6)	1,003.7	1,737.6	(88.7)	$ (1.6)	21.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	507.7				572.6		(64.9)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	47.7			47.7
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings	(64.6)			(64.6)
Exercise of stock options	64.9			64.9
Stock Issued During Period, Value, New Issues	967.0			967.0
Ending balance at Dec. 31, 2021	4,197.0		1,003.7	2,752.6	483.9		(43.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of junior convertible preferred stock			(1,003.7)	1,003.7
Comprehensive income (loss)	629.4				686.5		(57.1)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	49.1			49.1
Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings	(24.2)			(24.2)
Exercise of stock options	4.1			4.1
Ending balance at Dec. 31, 2022	$ 4,855.4		$ 0.0	$ 3,785.3	$ 1,170.4		$ (100.3)