Stockholders' Equity and Stock-Based Compensation (Summary of Share Activity) (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Preferred stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	3.4	3.4	1.7
Issuance of stock	0.0	0.0	1.7
Balance, end of period	1.7	3.4	3.4
Preferred stock | Convertible Preferred Stock Subject to Mandatory Redemption
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions	(1.7)	0.0	0.0
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	855.7	851.3	835.5
Issuance of stock	0.0	0.0	10.9
Issuance of common stock attributable to stock-based compensation	2.6	3.4	4.5
Common stock issued in connection with acquisitions	0.0	0.1	0.0
Balance, end of period	869.3	855.7	851.3
Common stock | Convertible Preferred Stock Subject to Mandatory Redemption
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions	11.0	0.0	0.0
Common stock | Liquid Yield Option Notes
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued in connection with MCPS and LYONs conversions	0.0	0.9	0.4