Stockholders' Deficit (Summary of Common Stock Repurchase) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Equity [Abstract]
Treasury Stock Shares Repurchased	$ 1.3
Treasury Stock Shares Repurchased for Tax Withholding and Other	$ 0.0
Common stock repurchase, share	1.4
Aggregate cost of share	$ 260.4
Treasury stock, value, repurchased for tax withholding	9.5
Payments for Repurchase of Common Stock	$ 269.9	$ 230.5
Treasury stock shares repurchased, average cost per share	$ 196.37
Total repurchases for tax withholdings and other, average cost per share	197.84
Average stock price	$ 196.42