Segment Information - Financial Information for Partnership's Reportable Segments (Detail) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($) Advisor	Sep. 27, 2019 USD ($)	Jun. 28, 2019 USD ($)	Mar. 29, 2019 USD ($)	Dec. 31, 2018 USD ($) Advisor	Sep. 28, 2018 USD ($)	Jun. 29, 2018 USD ($)	Mar. 30, 2018 USD ($)	Dec. 31, 2019 USD ($) Advisor	Dec. 31, 2018 USD ($) Advisor	Dec. 31, 2017 USD ($) Advisor
Net revenue:
Total net revenue	$ 2,493	$ 2,367	$ 2,319	$ 2,190	$ 2,153	$ 2,191	$ 2,083	$ 2,042	$ 9,369	$ 8,469	$ 7,506
Net interest and dividends revenue:
Total net interest and dividends revenue									259	237	174
Pre-variable income:
Total pre-variable income									2,210	1,988	1,685
Variable compensation:
Total variable compensation									1,118	998	813
Income (loss) before allocations to partners:
Total income before allocations to partners	285	$ 281	$ 285	$ 241	244	$ 273	$ 240	$ 233	1,092	990	872
Capital expenditures:
Total capital expenditures									176	105	80
Depreciation and amortization:
Depreciation and amortization									115	94	85
Total assets at year end:
Total assets	$ 19,317				$ 15,815				$ 19,317	$ 15,815	$ 17,176
Financial advisors at year end:
Total financial advisors | Advisor	18,704				17,615				18,704	17,615	16,095
United States [Member]
Net revenue:
Total net revenue									$ 9,127	$ 8,233	$ 7,305
Net interest and dividends revenue:
Total net interest and dividends revenue									249	228	170
Pre-variable income:
Total pre-variable income									2,194	1,972	1,681
Variable compensation:
Total variable compensation									1,094	975	795
Income (loss) before allocations to partners:
Total income before allocations to partners									1,100	997	886
Capital expenditures:
Total capital expenditures									170	102	78
Depreciation and amortization:
Depreciation and amortization									113	92	83
Total assets at year end:
Total assets	$ 18,577				$ 15,187				$ 18,577	$ 15,187	$ 16,563
Financial advisors at year end:
Total financial advisors | Advisor	17,830				16,797				17,830	16,797	15,347
Canada [Member]
Net revenue:
Total net revenue									$ 242	$ 236	$ 201
Net interest and dividends revenue:
Total net interest and dividends revenue									10	9	4
Pre-variable income:
Total pre-variable income									16	16	4
Variable compensation:
Total variable compensation									24	23	18
Income (loss) before allocations to partners:
Total income before allocations to partners									(8)	(7)	(14)
Capital expenditures:
Total capital expenditures									6	3	2
Depreciation and amortization:
Depreciation and amortization									2	2	2
Total assets at year end:
Total assets	$ 740				$ 628				$ 740	$ 628	$ 613
Financial advisors at year end:
Total financial advisors | Advisor	874				818				874	818	748