IMMATERIAL FINANCIAL RESTATEMENT AND RECLASSIFICATIONS TO PRIOR PERIOD FINANCIAL STATEMENTS - Changes in Equity (Details) - USD ($)
shares in Millions, $ in Millions |
3 Months Ended |
6 Months Ended |
9 Months Ended |
12 Months Ended |
Mar. 31, 2024 |
Sep. 30, 2023 |
Jun. 30, 2023 |
Mar. 31, 2023 |
Jun. 30, 2023 |
Sep. 30, 2023 |
Dec. 31, 2023 |
Dec. 31, 2022 |
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance (in shares) |
88.8
|
88.8
|
|
|
|
|
|
|
| Beginning balance |
$ 1,714.1
|
$ 1,747.8
|
$ 3,402.8
|
$ 3,340.0
|
$ 3,340.0
|
$ 3,340.0
|
$ 3,340.0
|
$ 3,261.4
|
| Net income (loss) |
(101.0)
|
(14.0)
|
30.8
|
12.5
|
43.3
|
29.3
|
(25.2)
|
186.2
|
| Other comprehensive income (loss), net of tax |
(26.1)
|
(54.4)
|
32.0
|
19.1
|
$ 51.1
|
(3.3)
|
59.3
|
(126.7)
|
| Special payment to Former Parent |
|
|
(1,595.0)
|
|
|
|
(1,595.0)
|
|
| Net transfers from Former Parent |
|
|
(122.9)
|
31.2
|
|
|
(91.7)
|
19.1
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
0.0
|
|
|
|
0.0
|
|
| Issuance of common stock |
|
|
$ 0.1
|
|
|
|
0.1
|
|
| Stock compensation |
$ 15.1
|
11.1
|
|
|
|
|
$ 26.6
|
|
| Ending balance (in shares) |
89.4
|
|
88.8
|
|
88.8
|
|
88.8
|
|
| Ending balance |
$ 1,591.9
|
$ 1,690.5
|
$ 1,747.8
|
$ 3,402.8
|
$ 1,747.8
|
$ 1,690.5
|
$ 1,714.1
|
$ 3,340.0
|
| Common Stock |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance (in shares) |
88.8
|
88.8
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Beginning balance |
$ 0.1
|
$ 0.1
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
| Issuance of common stock (in shares) |
0.6
|
|
88.8
|
|
|
|
88.8
|
|
| Issuance of common stock |
|
|
$ 0.1
|
|
|
|
$ 0.1
|
|
| Ending balance (in shares) |
89.4
|
88.8
|
88.8
|
0.0
|
88.8
|
88.8
|
88.8
|
0.0
|
| Ending balance |
$ 0.1
|
$ 0.1
|
$ 0.1
|
$ 0.0
|
$ 0.1
|
$ 0.1
|
$ 0.1
|
$ 0.0
|
| Additional Paid-in Capital |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
1,998.0
|
1,971.4
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
1,971.4
|
|
|
|
1,971.4
|
|
| Stock compensation |
15.1
|
11.1
|
|
|
|
|
26.6
|
|
| Ending balance |
2,002.9
|
1,982.5
|
1,971.4
|
0.0
|
1,971.4
|
1,982.5
|
1,998.0
|
0.0
|
| Former Parent Investment |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
0.0
|
0.0
|
3,658.5
|
3,614.8
|
3,614.8
|
3,614.8
|
3,614.8
|
3,409.5
|
| Net income (loss) |
|
|
30.8
|
12.5
|
|
|
43.3
|
186.2
|
| Special payment to Former Parent |
|
|
(1,595.0)
|
|
|
|
(1,595.0)
|
|
| Net transfers from Former Parent |
|
|
(122.9)
|
31.2
|
|
|
(91.7)
|
19.1
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
(1,971.4)
|
|
|
|
(1,971.4)
|
|
| Ending balance |
0.0
|
0.0
|
0.0
|
3,658.5
|
0.0
|
0.0
|
0.0
|
3,614.8
|
| Accumulated Deficit |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(68.5)
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Net income (loss) |
(101.0)
|
(14.0)
|
|
|
|
|
(68.5)
|
0.0
|
| Ending balance |
(169.5)
|
(14.0)
|
0.0
|
0.0
|
0.0
|
(14.0)
|
(68.5)
|
0.0
|
| Accumulated Other Comprehensive Loss |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(215.5)
|
(223.7)
|
(255.7)
|
(274.8)
|
(274.8)
|
(274.8)
|
(274.8)
|
(148.1)
|
| Other comprehensive income (loss), net of tax |
(26.1)
|
(54.4)
|
32.0
|
19.1
|
|
|
59.3
|
(126.7)
|
| Ending balance |
(241.6)
|
(278.1)
|
(223.7)
|
(255.7)
|
(223.7)
|
(278.1)
|
(215.5)
|
(274.8)
|
| As Previously Reported |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
$ 1,738.8
|
1,751.1
|
3,405.5
|
3,342.6
|
3,342.6
|
3,342.6
|
3,342.6
|
3,260.6
|
| Net income (loss) |
|
(13.1)
|
28.3
|
17.4
|
45.7
|
32.6
|
(3.4)
|
192.9
|
| Other comprehensive income (loss), net of tax |
|
(54.8)
|
31.6
|
18.9
|
50.5
|
(4.3)
|
57.6
|
(127.6)
|
| Special payment to Former Parent |
|
|
(1,595.0)
|
|
|
|
(1,595.0)
|
|
| Net transfers from Former Parent |
|
|
(119.4)
|
26.6
|
|
|
(89.7)
|
16.7
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
0.0
|
|
|
|
0.0
|
|
| Issuance of common stock |
|
|
0.1
|
|
|
|
0.1
|
|
| Stock compensation |
|
11.1
|
|
|
|
|
26.6
|
|
| Ending balance |
|
$ 1,694.3
|
$ 1,751.1
|
$ 3,405.5
|
$ 1,751.1
|
$ 1,694.3
|
$ 1,738.8
|
$ 3,342.6
|
| As Previously Reported | Common Stock |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance (in shares) |
88.8
|
88.8
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Beginning balance |
$ 0.1
|
$ 0.1
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
| Issuance of common stock (in shares) |
|
|
88.8
|
|
|
|
88.8
|
|
| Issuance of common stock |
|
|
$ 0.1
|
|
|
|
$ 0.1
|
|
| Ending balance (in shares) |
|
88.8
|
88.8
|
0.0
|
88.8
|
88.8
|
88.8
|
0.0
|
| Ending balance |
|
$ 0.1
|
$ 0.1
|
$ 0.0
|
$ 0.1
|
$ 0.1
|
$ 0.1
|
$ 0.0
|
| As Previously Reported | Additional Paid-in Capital |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
2,006.2
|
1,976.5
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
1,976.5
|
|
|
|
1,979.6
|
|
| Stock compensation |
|
11.1
|
|
|
|
|
26.6
|
|
| Ending balance |
|
1,987.6
|
1,976.5
|
0.0
|
1,976.5
|
1,987.6
|
2,006.2
|
0.0
|
| As Previously Reported | Former Parent Investment |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
0.0
|
0.0
|
3,662.6
|
3,618.6
|
3,618.6
|
3,618.6
|
3,618.6
|
3,409.0
|
| Net income (loss) |
|
|
28.3
|
17.4
|
|
|
45.7
|
192.9
|
| Special payment to Former Parent |
|
|
(1,595.0)
|
|
|
|
(1,595.0)
|
|
| Net transfers from Former Parent |
|
|
(119.4)
|
26.6
|
|
|
(89.7)
|
16.7
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
(1,976.5)
|
|
|
|
(1,979.6)
|
|
| Ending balance |
|
0.0
|
0.0
|
3,662.6
|
0.0
|
0.0
|
0.0
|
3,618.6
|
| As Previously Reported | Accumulated Deficit |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(49.1)
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Net income (loss) |
|
(13.1)
|
|
|
|
|
(49.1)
|
0.0
|
| Ending balance |
|
(13.1)
|
0.0
|
0.0
|
0.0
|
(13.1)
|
(49.1)
|
0.0
|
| As Previously Reported | Accumulated Other Comprehensive Loss |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(218.4)
|
(225.5)
|
(257.1)
|
(276.0)
|
(276.0)
|
(276.0)
|
(276.0)
|
(148.4)
|
| Other comprehensive income (loss), net of tax |
|
(54.8)
|
31.6
|
18.9
|
|
|
57.6
|
(127.6)
|
| Ending balance |
|
(280.3)
|
(225.5)
|
(257.1)
|
(225.5)
|
(280.3)
|
(218.4)
|
(276.0)
|
| Adjustments |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
$ (24.7)
|
(3.3)
|
(2.7)
|
(2.6)
|
(2.6)
|
(2.6)
|
(2.6)
|
0.8
|
| Net income (loss) |
|
(0.9)
|
2.5
|
(4.9)
|
(2.4)
|
(3.3)
|
(21.8)
|
(6.7)
|
| Other comprehensive income (loss), net of tax |
|
0.4
|
0.4
|
0.2
|
0.6
|
1.0
|
1.7
|
0.9
|
| Net transfers from Former Parent |
|
|
(3.5)
|
4.6
|
|
|
(2.0)
|
2.4
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
0.0
|
|
|
|
0.0
|
|
| Ending balance |
|
$ (3.8)
|
$ (3.3)
|
$ (2.7)
|
$ (3.3)
|
$ (3.8)
|
$ (24.7)
|
$ (2.6)
|
| Adjustments | Common Stock |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance (in shares) |
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Beginning balance |
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
| Ending balance (in shares) |
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Ending balance |
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
$ 0.0
|
| Adjustments | Additional Paid-in Capital |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(8.2)
|
(5.1)
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
(5.1)
|
|
|
|
(8.2)
|
|
| Ending balance |
|
(5.1)
|
(5.1)
|
0.0
|
(5.1)
|
(5.1)
|
(8.2)
|
0.0
|
| Adjustments | Former Parent Investment |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
0.0
|
0.0
|
(4.1)
|
(3.8)
|
(3.8)
|
(3.8)
|
(3.8)
|
0.5
|
| Net income (loss) |
|
|
2.5
|
(4.9)
|
|
|
(2.4)
|
(6.7)
|
| Net transfers from Former Parent |
|
|
(3.5)
|
4.6
|
|
|
(2.0)
|
2.4
|
| Reclassification of Former Parent investment to additional paid-in capital |
|
|
5.1
|
|
|
|
8.2
|
|
| Ending balance |
|
0.0
|
0.0
|
(4.1)
|
0.0
|
0.0
|
0.0
|
(3.8)
|
| Adjustments | Accumulated Deficit |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
(19.4)
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
0.0
|
| Net income (loss) |
|
(0.9)
|
|
|
|
|
(19.4)
|
0.0
|
| Ending balance |
|
(0.9)
|
0.0
|
0.0
|
0.0
|
(0.9)
|
(19.4)
|
0.0
|
| Adjustments | Accumulated Other Comprehensive Loss |
|
|
|
|
|
|
|
|
| Increase (Decrease) in Stockholders' Equity [Roll Forward] |
|
|
|
|
|
|
|
|
| Beginning balance |
$ 2.9
|
1.8
|
1.4
|
1.2
|
1.2
|
1.2
|
1.2
|
0.3
|
| Other comprehensive income (loss), net of tax |
|
0.4
|
0.4
|
0.2
|
|
|
1.7
|
0.9
|
| Ending balance |
|
$ 2.2
|
$ 1.8
|
$ 1.4
|
$ 1.8
|
$ 2.2
|
$ 2.9
|
$ 1.2
|