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Fair Value Measurements - Changes in Level 3 Liabilities (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Contingent Payment Obligations |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, beginning of period | $ 9.6 | $ 22.9 | $ 14.7 | $ 21.0
Purchases and issuances | 0.0 | 0.0 | 0.0 | 0.0
Settlements and reductions | 0.0 | 0.0 | 0.0 | 0.0
Net realized and unrealized (gains) losses | (1.7) | 0.5 | (6.8) | 2.4
Balance, end of period | 7.9 | 23.4 | 7.9 | 23.4
Net change in unrealized (gains) losses relating to instruments still held at the reporting date | (1.7) | 0.5 | (6.8) | 2.4
Affiliate Equity Purchase Obligations |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, beginning of period | 37.7 | 60.9 | 53.9 | 24.5
Purchases and issuances | 31.3 | 26.8 | 56.2 | 71.0
Settlements and reductions | (16.6) | (16.8) | (57.1) | (24.3)
Net realized and unrealized (gains) losses | 1.5 | (2.5) | 0.9 | (2.8)
Balance, end of period | 53.9 | 68.4 | 53.9 | 68.4
Net change in unrealized (gains) losses relating to instruments still held at the reporting date | $ 1.5 | $ (1.8) | $ 0.9 | $ (2.1)

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- Definition Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Settlements And Reductions + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3) and still held. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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- Definition Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
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