Fair Value Measurements (Financial Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2019		Dec. 31, 2018
Deferred compensation plan investments (1)	$ 143.5	[1]	$ 144.7
Participant Withdrawals From Deferred Compensation Plan Investments	19.1		12.7
Interest Rate Derivative Liabilities, at Fair Value	0.0		7.4
Level 1 [Member]
Deferred compensation plan investments (1)	143.5	[1]	144.7
Interest Rate Derivative Liabilities, at Fair Value	0.0		0.0
Level 2 [Member]
Deferred compensation plan investments (1)	0.0	[1]	0.0
Level 3 [Member]
Deferred compensation plan investments (1)	0.0	[1]	0.0
Interest Rate Derivative Liabilities, at Fair Value	0.0		0.0
Interest Rate Swap [Member]
Interest Rate Derivative Assets, at Fair Value	0.0		0.0
Interest Rate Derivative Liabilities, at Fair Value	0.0		7.4
Interest Rate Swap [Member] | Level 2 [Member]
Interest Rate Derivative Liabilities, at Fair Value	$ 0.0		$ 7.4

[1] Approximately $19.1 million and $12.7 million of participant cash was withdrawn from our deferred compensation plan investments during the nine months ended September 30, 2019 and the year ended December 31, 2018, respectively.