Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring - USD ($)
$ in Millions |
Mar. 31, 2021 |
Dec. 31, 2020 |
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Cash and cash equivalents |
$ 1,774.5
|
$ 1,789.7
|
| Restricted cash |
64.0
|
71.4
|
| Short-term investment securities |
106.4
|
106.3
|
| Assets held for sale |
2.3
|
2.3
|
| Total assets |
1,947.2
|
1,969.7
|
| Total liabilities |
0.0
|
0.0
|
| Level 1 |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Cash and cash equivalents |
1,774.5
|
1,789.7
|
| Restricted cash |
64.0
|
71.4
|
| Short-term investment securities |
106.4
|
106.3
|
| Assets held for sale |
0.0
|
0.0
|
| Total assets |
1,944.9
|
1,967.4
|
| Total liabilities |
0.0
|
0.0
|
| Level 2 |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Cash and cash equivalents |
0.0
|
0.0
|
| Restricted cash |
0.0
|
0.0
|
| Short-term investment securities |
0.0
|
0.0
|
| Assets held for sale |
0.0
|
0.0
|
| Total assets |
0.0
|
0.0
|
| Total liabilities |
0.0
|
0.0
|
| Level 3 |
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Cash and cash equivalents |
0.0
|
0.0
|
| Restricted cash |
0.0
|
0.0
|
| Short-term investment securities |
0.0
|
0.0
|
| Assets held for sale |
2.3
|
2.3
|
| Total assets |
2.3
|
2.3
|
| Total liabilities |
$ 0.0
|
$ 0.0
|