Stockholders' Equity - Statement of Changes in Common Shares Outstanding (Details) - shares shares in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Class A Common Stock | |||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | |||
| Purchases of treasury stock | (23.0) | (23.8) | (25.7) |
| Common Stock | Class A Common Stock | |||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | |||
| Balance | 927.3 | 948.4 | 972.1 |
| Purchases of treasury stock | (23.0) | (23.8) | (25.7) |
| Share-based payments | 1.9 | 2.3 | 1.8 |
| Conversion of Class B to Class A common stock | 0.4 | 0.4 | 0.2 |
| Balance | 906.6 | 927.3 | 948.4 |
| Common Stock | Class B Common Stock | |||
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | |||
| Balance | 7.2 | 7.6 | 7.8 |
| Conversion of Class B to Class A common stock | (0.4) | (0.4) | (0.2) |
| Balance | 6.8 | 7.2 | 7.6 |