Fair Value Measurements - Carrying Amount and Fair Value of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Publicly traded debt | Carrying Amount
Debt Instrument [Line Items]
Debt fair value	$ 8,849.6	$ 8,265.2	$ 8,203.2
Publicly traded debt | Fair Value
Debt Instrument [Line Items]
Debt fair value	9,777.4	9,707.0	8,735.8
Non-traded debt | Carrying Amount
Debt Instrument [Line Items]
Debt fair value	1.9	26.8	277.3
Non-traded debt | Fair Value
Debt Instrument [Line Items]
Debt fair value	$ 1.9	$ 26.5	$ 270.7