Segment Reporting (Summary Of The Operating Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,429,428	$ 1,340,073	$ 4,250,366	$ 4,000,661
Cost of Revenue	271,778	230,332	793,655	700,393
Operating expenses	1,068,873	902,585	3,038,873	2,689,610
Total costs and expenses	1,340,651	1,132,917	3,832,528	3,390,003
Operating earnings (loss)	88,777	207,156	417,838	610,658
Domestic Segment
Segment Reporting Information [Line Items]
Revenues	1,265,263	1,188,154	3,762,205	3,525,314
Cost of Revenue	246,634	202,980	719,119	617,839
Operating expenses	639,590	532,958	1,817,244	1,604,297
Total costs and expenses	886,224	735,938	2,536,363	2,222,136
Operating earnings (loss)	379,039	452,216	1,225,842	1,303,178
International Segment [Member]
Segment Reporting Information [Line Items]
Revenues	164,165	151,919	488,161	475,347
Cost of Revenue	25,144	27,352	74,536	82,554
Operating expenses	68,153	67,220	209,580	209,771
Total costs and expenses	93,297	94,572	284,116	292,325
Operating earnings (loss)	70,868	57,347	204,045	183,022
Other
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Operating expenses	361,130	302,407	1,012,049	875,542
Total costs and expenses	361,130	302,407	1,012,049	875,542
Operating earnings (loss)	$ (361,130)	$ (302,407)	$ (1,012,049)	$ (875,542)