Segment Reporting (Summary Of The Operating Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 29, 2019	Jun. 30, 2020	Jun. 29, 2019
Segment Reporting Information [Line Items]
Revenues	$ 1,330,349	$ 1,431,061	$ 2,742,090	$ 2,820,938
Cost of revenues	211,963	268,673	466,379	521,877
Operating expenses	971,488	1,031,271	1,950,437	1,970,000
Total costs and expenses	1,183,451	1,299,944	2,416,816	2,491,877
Operating earnings (loss)	146,898	131,117	325,274	329,061
Domestic Segment
Segment Reporting Information [Line Items]
Revenues	1,168,213	1,266,112	2,414,628	2,496,942
Cost of revenues	189,779	243,926	418,346	472,485
Operating expenses	587,674	605,636	1,157,768	1,177,654
Total costs and expenses	777,453	849,562	1,576,114	1,650,139
Operating earnings (loss)	390,760	416,550	838,514	846,803
International Segment [Member]
Segment Reporting Information [Line Items]
Revenues	162,136	164,949	327,462	323,996
Cost of revenues	22,184	24,747	48,033	49,392
Operating expenses	57,413	73,258	123,968	141,427
Total costs and expenses	79,597	98,005	172,001	190,819
Operating earnings (loss)	82,539	66,944	155,461	133,177
Other
Segment Reporting Information [Line Items]
Operating expenses	326,401	352,377	668,701	650,919
Total costs and expenses	326,401	352,377	668,701	650,919
Operating earnings (loss)	$ (326,401)	$ (352,377)	$ (668,701)	$ (650,919)