Fair Value Measurements - Financial Assets and Liabilities Measured on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 82.2	$ 72.6
Redeemable noncontrolling interests	42.2	31.6
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	4.1	0.0
Redeemable noncontrolling interests	0.0	0.0
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	78.1	72.6
Redeemable noncontrolling interests	0.0	0.0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0.0	0.0
Redeemable noncontrolling interests	$ 42.2	$ 31.6