Stockholders' Equity and Stock-Based Compensation (Summary of Share Activity) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Preferred stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	1.7	3.4	3.4
Balance, end of period	0.0	1.7	3.4
Preferred stock | Conversion of MCPS to common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions (in shares)	(1.7)	(1.7)	0.0
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	869.3	855.7	851.3
Issuance of common stock attributable to stock-based compensation	2.6	2.6	3.4
Common stock issued in connection with acquisitions	0.0	0.0	0.1
Balance, end of period	880.5	869.3	855.7
Common stock | Conversion of MCPS to common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions (in shares)	8.6	11.0	0.0
Common stock | Common stock issued in connection with LYONs’ conversions
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions (in shares)	0.0	0.0	0.9