Partnership Capital Subject to Mandatory Redemption - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020	Dec. 31, 2020	Dec. 31, 2019	Jan. 12, 2018
Partners Capital Account [Line Items]
Period of loans made by Partnership to general partners			1 year		1 year
Percentage of interest made by partnership to general partners			3.25%		3.25%
Outstanding amount of partner loans financed through the Partnership	$ 336	$ 363	$ 336	$ 363	$ 341	$ 360
Interest income from outstanding amount of general partner loan	$ 3	$ 3	$ 10	$ 11
Limited partnership's minimum annual return rate	7.50%	7.50%	7.50%	7.50%
Limited partnership's minimum return, value	$ 23	$ 23	$ 69	$ 70
2018 Limited Partnership Offering [Member]
Partners Capital Account [Line Items]
Limited partnership amount registered							$ 450
Limited partnership interests issued	5		5		$ 1
Remaining limited partnership interests that may be issued	$ 64		$ 64