Valuation And Qualifying Accounts (Details) - Allowance for doubtful accounts, loan credit losses, and sales returns - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 20.4	$ 14.6	$ 10.8
Additions	46.9	46.0	36.1
Deductions	(45.9)	(40.2)	(32.3)
Balance at End of Year	$ 21.4	$ 20.4	$ 14.6