Related Parties - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Rent and other lease-related expenses			$ 305,000,000
Lease right-of-use assets	$ 915,000,000	$ 876,000,000
Lease liabilities	938,000,000	898,000,000
Passport Research, Ltd [Member]
Related Party Transaction [Line Items]
Total fees waived	$ 7,000,000	0	0
Financial Advisor [Member] | Edward D. Jones & Co., L. P [Member]
Related Party Transaction [Line Items]
Percentage of branch office space leased from its financial advisors	11.00%
Lease cost	$ 35,000,000	34,000,000
Rent and other lease-related expenses			32,000,000
Lease right-of-use assets	89,000,000	83,000,000
Lease liabilities	89,000,000	83,000,000
BB Trust [Member] | Olive Street [Member]
Related Party Transaction [Line Items]
Expense paid to sub-advisers	174,000,000	147,000,000	123,000,000
Investment advisory fee revenue	174,000,000	147,000,000	123,000,000
Edward Jones Money Market Fund [Member] | Edward D. Jones & Co., L. P [Member]
Related Party Transaction [Line Items]
Total fees earned	46,000,000	138,000,000	113,000,000
Total fees voluntarily waived to limit fund expenses	133,000,000	30,000,000	30,000,000
Edward Jones Money Market Fund [Member] | Passport Research, Ltd [Member]
Related Party Transaction [Line Items]
Investment advisory fee revenue	$ 56,000,000	$ 58,000,000	$ 48,000,000