Introduction and Basis of Presentation (Policies)	3 Months Ended
Mar. 29, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Partnership's Business and Basis of Accounting	The accompanying Consolidated Financial Statements include the accounts of The Jones Financial Companies, L.L.L.P. and all wholly-owned subsidiaries (collectively, the “Partnership” or "JFC"). All material intercompany balances and transactions have been eliminated in consolidation. The financial position of the Partnership’s subsidiaries in Canada as of February 28, 2019 and November 30, 2018 are included in the Partnership’s Consolidated Statements of Financial Condition and the results for the three month periods ended February 28, 2019 and 2018 are included in the Partnership’s Consolidated Statements of Income, Consolidated Statements of Changes in Partnership Capital Subject to Mandatory Redemption, and Consolidated Statements of Cash Flows because of the timing of the Partnership’s financial reporting process. The Partnership’s principal operating subsidiary, Edward D. Jones & Co., L.P. (“Edward Jones”), is a registered broker-dealer and investment adviser in the United States (“U.S.”), and one of Edward Jones’ subsidiaries is a registered broker-dealer in Canada. Through these entities, the Partnership primarily serves individual investors in the U.S. and Canada. Edward Jones is a retail brokerage business and primarily derives revenues from fees for providing investment advisory and other account services to its clients, fees for assets held by clients, the distribution of mutual fund shares, and commissions for the purchase or sale of securities and the purchase of insurance products. The Partnership conducts business throughout the U.S. and Canada with its clients, various brokers, dealers, clearing organizations, depositories and banks. Trust services are offered to Edward Jones’ U.S. clients through Edward Jones Trust Company (“Trust Co.”), a wholly-owned subsidiary of the Partnership. Olive Street Investment Advisers, LLC, a wholly-owned subsidiary of the Partnership, provides investment advisory services to the sub-advised mutual funds in the Bridge Builder® Trust ("BB Trust"). Passport Research, Ltd., a wholly-owned subsidiary of the Partnership, provides investment advisory services to the Edward Jones Money Market Fund (the "Fund"). The Consolidated Financial Statements have been prepared on the accrual basis of accounting in conformity with U.S. generally accepted accounting principles (“GAAP”), which require the use of certain estimates by management in determining the Partnership’s assets, liabilities, revenues and expenses. Actual results could differ from these estimates. The Partnership has evaluated subsequent events through the date these Consolidated Financial Statements were issued and identified no matters requiring disclosure. The interim financial information included herein is unaudited. However, in the opinion of management, such information includes all adjustments, consisting primarily of normal recurring accruals, which are necessary for a fair statement of the results of interim operations. There have been no material changes to the Partnership’s significant accounting policies or disclosures of recently issued accounting standards as described in Part II, Item 8 – Financial Statements and Supplementary Data – Note 1 of the Partnership's Annual Report on Form 10-K for the year ended December 31, 2018 (the "Annual Report"), except as disclosed in Note 2 herein. The results of operations for the three month period ended March 29, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019. These unaudited Consolidated Financial Statements should be read in conjunction with Management's Discussion and Analysis of Financial Condition and Results of Operations and the Consolidated Financial Statements and notes thereto included in the Annual Report.
Fair Value	The Partnership's valuation methodologies for financial assets and financial liabilities measured at fair value and the fair value hierarchy are described in Part II, Item 8 – Financial Statements and Supplementary Data – Note 1 of the Partnership's Annual Report. There have been no material changes to the Partnership's valuation methodologies since December 31, 2018
Contingencies (ASC No.450)	The Partnership assesses its liabilities and contingencies utilizing available information. The Partnership accrues for potential losses for those matters where it is probable that the Partnership will incur a potential loss to the extent that the amount of such potential loss can be reasonably estimated, in accordance with FASB Accounting Standards Codification No. 450, Contingencies. This liability represents the Partnership’s estimate of the probable loss at March 29, 2019, after considering, among other factors, the progress of each case, the Partnership's experience with other legal and regulatory matters and discussion with legal counsel, and is believed to be sufficient. The aggregate accrued liability may be adjusted from time to time to reflect any relevant developments.

Introduction and Basis of Presentation (Policies)

3 Months Ended

Mar. 29, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

The Partnership's Business and Basis of Accounting

The accompanying Consolidated Financial Statements include the accounts of The Jones Financial Companies, L.L.L.P. and all wholly-owned subsidiaries (collectively, the “Partnership” or "JFC"). All material intercompany balances and transactions have been eliminated in consolidation. The financial position of the Partnership’s subsidiaries in Canada as of February 28, 2019 and November 30, 2018 are included in the Partnership’s Consolidated Statements of Financial Condition and the results for the three month periods ended February 28, 2019 and 2018 are included in the Partnership’s Consolidated Statements of Income, Consolidated Statements of Changes in Partnership Capital Subject to Mandatory Redemption, and Consolidated Statements of Cash Flows because of the timing of the Partnership’s financial reporting process.

The Partnership’s principal operating subsidiary, Edward D. Jones & Co., L.P. (“Edward Jones”), is a registered broker-dealer and investment adviser in the United States (“U.S.”), and one of Edward Jones’ subsidiaries is a registered broker-dealer in Canada. Through these entities, the Partnership primarily serves individual investors in the U.S. and Canada. Edward Jones is a retail brokerage business and primarily derives revenues from fees for providing investment advisory and other account services to its clients, fees for assets held by clients, the distribution of mutual fund shares, and commissions for the purchase or sale of securities and the purchase of insurance products. The Partnership conducts business throughout the U.S. and Canada with its clients, various brokers, dealers, clearing organizations, depositories and banks. Trust services are offered to Edward Jones’ U.S. clients through Edward Jones Trust Company (“Trust Co.”), a wholly-owned subsidiary of the Partnership. Olive Street Investment Advisers, LLC, a wholly-owned subsidiary of the Partnership, provides investment advisory services to the sub-advised mutual funds in the Bridge Builder® Trust ("BB Trust"). Passport Research, Ltd., a wholly-owned subsidiary of the Partnership, provides investment advisory services to the Edward Jones Money Market Fund (the "Fund").

The Consolidated Financial Statements have been prepared on the accrual basis of accounting in conformity with U.S. generally accepted accounting principles (“GAAP”), which require the use of certain estimates by management in determining the Partnership’s assets, liabilities, revenues and expenses. Actual results could differ from these estimates. The Partnership has evaluated subsequent events through the date these Consolidated Financial Statements were issued and identified no matters requiring disclosure.

The interim financial information included herein is unaudited. However, in the opinion of management, such information includes all adjustments, consisting primarily of normal recurring accruals, which are necessary for a fair statement of the results of interim operations.

There have been no material changes to the Partnership’s significant accounting policies or disclosures of recently issued accounting standards as described in Part II, Item 8 – Financial Statements and Supplementary Data – Note 1 of the Partnership's Annual Report on Form 10-K for the year ended December 31, 2018 (the "Annual Report"), except as disclosed in Note 2 herein. The results of operations for the three month period ended March 29, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019. These unaudited Consolidated Financial Statements should be read in conjunction with Management's Discussion and Analysis of Financial Condition and Results of Operations and the Consolidated Financial Statements and notes thereto included in the Annual Report.

Fair Value

The Partnership's valuation methodologies for financial assets and financial liabilities measured at fair value and the fair value hierarchy are described in Part II, Item 8 – Financial Statements and Supplementary Data – Note 1 of the Partnership's Annual Report. There have been no material changes to the Partnership's valuation methodologies since December 31, 2018

Contingencies (ASC No.450)

The Partnership assesses its liabilities and contingencies utilizing available information. The Partnership accrues for potential losses for those matters where it is probable that the Partnership will incur a potential loss to the extent that the amount of such potential loss can be reasonably estimated, in accordance with FASB Accounting Standards Codification No. 450, Contingencies. This liability represents the Partnership’s estimate of the probable loss at March 29, 2019, after considering, among other factors, the progress of each case, the Partnership's experience with other legal and regulatory matters and discussion with legal counsel, and is believed to be sufficient. The aggregate accrued liability may be adjusted from time to time to reflect any relevant developments.