Temporarily Impaired Available for Sale Debt Securities by Time Period Impaired (Details) - USD ($) $ in Thousands	Mar. 26, 2022	Dec. 25, 2021
Debt Securities, Available-for-sale [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 6,056,357	$ 4,242,438
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	332,638	73,221
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,876,835	1,131,942
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	178,894	36,044
Unrealized Loss Position, Fair Value	7,933,192	5,374,380
Unrealized Loss Position, Accumulated Loss	511,532	109,265
Tax exempt bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	89,564	0
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	142	0
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	0	0
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Unrealized Loss Position, Fair Value	89,564	0
Unrealized Loss Position, Accumulated Loss	142	0
Taxable bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	5,959,756	4,225,323
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	331,921	72,862
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,867,847	1,131,942
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	178,102	36,044
Unrealized Loss Position, Fair Value	7,827,603	5,357,265
Unrealized Loss Position, Accumulated Loss	510,023	108,906
Restricted investments [Member]
Debt Securities, Available-for-sale [Line Items]
Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	7,037	17,115
Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	575	359
Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	8,988	0
Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	792	0
Unrealized Loss Position, Fair Value	16,025	17,115
Unrealized Loss Position, Accumulated Loss	$ 1,367	$ 359