Segment Reporting (Summary Of The Operating Information) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 1,411,741	$ 1,389,877
Cost of revenues	254,416	253,204
Operating expenses	978,949	938,729
Total costs and expenses	1,233,365	1,191,933
Operating earnings (loss)	178,376	197,944
Domestic Segment
Segment Reporting Information [Line Items]
Revenues	1,246,415	1,230,830
Cost of revenues	228,567	228,559
Operating expenses	570,094	572,018
Total costs and expenses	798,661	800,577
Operating earnings (loss)	447,754	430,253
International Segment [Member]
Segment Reporting Information [Line Items]
Revenues	165,326	159,047
Cost of revenues	25,849	24,645
Operating expenses	66,555	68,169
Total costs and expenses	92,404	92,814
Operating earnings (loss)	72,922	66,233
Other
Segment Reporting Information [Line Items]
Operating expenses	342,300	298,542
Total costs and expenses	342,300	298,542
Operating earnings (loss)	$ (342,300)	$ (298,542)