Fair Value Measurements Fair Value Measurements (Reconciliation of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs) (Details) - USD ($)
$ in Millions

3 Months Ended

6 Months Ended

Jun. 30, 2024

Jun. 30, 2023

Jun. 30, 2024

Jun. 30, 2023

Mar. 31, 2024

Dec. 31, 2023

Mar. 31, 2023

Dec. 31, 2022

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Investments, Fair Value Disclosure

$ 744.7

$ 802.5

$ 744.7

$ 802.5

$ 740.8

$ 794.9

Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]

Investments, Fair Value Disclosure

367.8

64.3

367.8

64.3

$ 369.7

$ 367.3

$ 466.5

$ 452.0

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Business Combination, Contingent Consideration, Liability, Beginning Balance

46.7

73.1

57.5

73.2

Derivative Assets (Liabilities), at Fair Value, Net, Beginning Balance

18.9

12.8

10.3

20.7

Business Combination, Contingent Consideration, Liability, Ending Balance

53.7

438.1

53.7

438.1

Derivative Assets (Liabilities), at Fair Value, Net, Ending Balance

31.7

59.1

31.7

59.1

Earn-out Liabilities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings

(2.1)

(0.6)

(12.6)

(0.6)

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)

0.0

0.2

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases

11.0

0.0

11.0

0.0

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements

(1.7)

(8.2)

(2.0)

(8.5)

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3

(0.2)

0.0

(0.2)

0.0

Derivative [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings

19.5

43.9

28.2

38.9

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)

0.0

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases

22.3

37.4

46.1

68.5

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements

(29.0)

(35.0)

(52.9)

(69.0)

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3

0.0

Investments [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings

(9.3)

(103.9)

(10.4)

(99.0)

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)

(0.1)

0.7

(0.3)

1.2

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases

2.3

11.0

2.8

20.1

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements

0.0

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3

$ 5.2

$ 63.8

$ 8.4

$ 63.8