TD Ameritrade Holding 10-Q 1 Aug 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Jun. 30, 2019	Jul. 24, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	1-35509
Entity Registrant Name	TD Ameritrade Holding Corporation
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-0543156
Entity Address, Address Line One	200 South 108th Avenue
Entity Address, City or Town	Omaha
Entity Address, State or Province	NE
Entity Address, Postal Zip Code	68154
City Area Code	800
Local Phone Number	669-3900
Title of 12(b) Security	Common stock – $0.01 par value
Trading Symbol	AMTD
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		548,523,530
Amendment Flag	false
Entity Central Index Key	0001173431
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
ASSETS
Cash and cash equivalents	$ 2,953	$ 2,690
Cash and investments segregated and on deposit for regulatory purposes	7,124	3,185
Receivable from brokers, dealers and clearing organizations	1,780	1,374
Receivable from clients, net	20,847	22,616
Receivable from affiliates	127	151
Other receivables, net	260	304
Securities owned, at fair value	318	156
Investments available-for-sale, at fair value	1,129	484
Property and equipment at cost, net	833	792
Goodwill	4,227	4,227
Acquired intangible assets, net	1,236	1,329
Other assets	285	212
Total assets	41,119	37,520
Liabilities:
Payable to brokers, dealers and clearing organizations	3,210	2,980
Payable to clients	24,588	22,884
Accounts payable and other liabilities	1,032	896
Payable to affiliates	3	45
Other borrowings	0	96
Long-term debt	3,574	2,439
Deferred income taxes	219	177
Total liabilities	32,626	29,517
Stockholders' equity:
Preferred stock, $0.01 par value; 100 million shares authorized, none issued	0	0
Common stock, $0.01 par value; one billion shares authorized; 670 million shares issued; June 30, 2019 – 550 million shares outstanding; September 30, 2018 – 563 million shares outstanding	7	7
Additional paid-in capital	3,355	3,379
Retained earnings	8,194	7,011
Treasury stock, common, at cost: June 30, 2019 – 120 million shares; September 30, 2018 – 107 million shares	(3,074)	(2,371)
Deferred compensation	4	4
Accumulated other comprehensive income (loss)	7	(27)
Total stockholders' equity	8,493	8,003
Total liabilities and stockholders' equity	$ 41,119	$ 37,520

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Sep. 30, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	670,000,000	670,000,000
Common stock, shares outstanding (in shares)	550,000,000	563,000,000
Treasury stock, shares (in shares)	120,000,000	107,000,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Transaction-based revenues:
Commissions and transaction fees	$ 477	$ 490	$ 1,500	$ 1,487
Asset-based revenues:
Bank deposit account fees	421	387	1,280	1,149
Net interest revenue	383	332	1,120	916
Investment product fees	151	140	431	414
Total asset-based revenues	955	859	2,831	2,479
Other revenues	59	33	126	88
Net revenues	1,491	1,382	4,457	4,054
Operating expenses:
Employee compensation and benefits	325	352	982	1,228
Clearing and execution costs	59	46	161	149
Communications	39	42	119	141
Occupancy and equipment costs	67	67	199	226
Depreciation and amortization	38	37	109	106
Amortization of acquired intangible assets	31	32	93	107
Professional services	71	70	218	230
Advertising	80	63	213	218
Other	61	42	142	286
Total operating expenses	771	751	2,236	2,691
Operating income	720	631	2,221	1,363
Other expense (income):
Interest on borrowings	37	28	107	72
Gain on business-related divestiture	(60)	0	(60)	0
Loss on sale of investments	0	0	0	11
Other	0	0	(14)	2
Total other expense (income)	(23)	28	33	85
Pre-tax income	743	603	2,188	1,278
Provision for income taxes	188	152	530	259
Net income	$ 555	$ 451	$ 1,658	$ 1,019
Earnings per share - basic (in USD per share)	$ 1.01	$ 0.79	$ 2.97	$ 1.80
Earnings per share - diluted (in USD per share)	$ 1	$ 0.79	$ 2.96	$ 1.79
Weighted average shares outstanding - basic (in shares)	552	568	558	567
Weighted average shares outstanding - diluted (in shares)	554	570	560	570

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 555	$ 451	$ 1,658	$ 1,019
Investments available-for-sale:
Unrealized gain (loss)	17	(2)	42	(8)
Reclassification adjustment for realized loss included in net income	0	0	0	11
Net change in investments available-for-sale	17	(2)	42	3
Cash flow hedging instruments:
Reclassification adjustment for portion of realized loss amortized to net income	1	1	3	3
Total other comprehensive income (loss), before tax	18	(1)	45	6
Income tax effect	(5)	0	(11)	(3)
Total other comprehensive income (loss), net of tax	13	(1)	34	3
Comprehensive income	$ 568	$ 450	$ 1,692	$ 1,022

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Deferred Compensation [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance, value at Sep. 30, 2017	$ 7,247	$ 7	$ 3,369	$ 6,011	$ (2,116)	$ 1	$ (25)
Beginning balance (in shares) at Sep. 30, 2017		567
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,019			1,019
Other comprehensive income (loss), net of tax	3						3
Common stock dividends	(357)			(357)
Repurchases of common stock for income tax withholding on stock-based compensation	(16)				(16)
Common stock issued for stock-based compensation, including tax effects	0		(14)		14
Common stock issued for stock-based compensation, including tax effects (in shares)		1
Deferred compensation	1		1
Stock-based compensation	39		39
Ending balance, value at Jun. 30, 2018	7,936	$ 7	3,395	6,673	(2,118)	1	(22)
Ending balance (in shares) at Jun. 30, 2018		568
Beginning balance, value at Mar. 31, 2018	7,595	$ 7	3,387	6,341	(2,120)	1	(21)
Beginning balance (in shares) at Mar. 31, 2018		567
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	451			451
Other comprehensive income (loss), net of tax	(1)						(1)
Common stock dividends	(119)			(119)
Repurchases of common stock for income tax withholding on stock-based compensation	(3)				(3)
Common stock issued for stock-based compensation, including tax effects	0		(5)		5
Common stock issued for stock-based compensation, including tax effects (in shares)		1
Stock-based compensation	13		13
Ending balance, value at Jun. 30, 2018	7,936	$ 7	3,395	6,673	(2,118)	1	(22)
Ending balance (in shares) at Jun. 30, 2018		568
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of Accounting Standards Update 2014-09 (Note 16)	28			28
Beginning balance, value at Sep. 30, 2018	$ 8,003	$ 7	3,379	7,011	(2,371)	4	(27)
Beginning balance (in shares) at Sep. 30, 2018	563	563
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 1,658			1,658
Other comprehensive income (loss), net of tax	34						34
Common stock dividends	(503)			(503)
Repurchases of common stock	(673)		31		(704)
Repurchases of common stock (in shares)		(14)
Future treasury stock purchases under accelerated stock repurchase agreement	(74)		(74)
Repurchases of common stock for income tax withholding on stock-based compensation	(12)				(12)
Common stock issued for stock-based compensation, including tax effects	0		(13)		13
Common stock issued for stock-based compensation, including tax effects (in shares)		1
Stock-based compensation	32		32
Ending balance, value at Jun. 30, 2019	$ 8,493	$ 7	3,355	8,194	(3,074)	4	7
Ending balance (in shares) at Jun. 30, 2019	550	550
Beginning balance, value at Mar. 31, 2019	$ 8,323	$ 7	3,345	7,805	(2,832)	4	(6)
Beginning balance (in shares) at Mar. 31, 2019		554
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	555			555
Other comprehensive income (loss), net of tax	13						13
Common stock dividends	(166)			(166)
Repurchases of common stock	(242)				(242)
Repurchases of common stock (in shares)		(4)
Stock-based compensation	10		10
Ending balance, value at Jun. 30, 2019	$ 8,493	$ 7	$ 3,355	$ 8,194	$ (3,074)	$ 4	$ 7
Ending balance (in shares) at Jun. 30, 2019	550	550

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Stockholders' Equity [Abstract]
Common stock dividends (in dollars per share)	$ 0.30	$ 0.21	$ 0.90	$ 0.63

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 1,658	$ 1,019
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	109	106
Amortization of acquired intangible assets	93	107
Deferred income taxes	26	(38)
Gain on business-related divestiture	(60)	0
Loss on sale of investments	0	11
Stock-based compensation	32	39
Provision for doubtful accounts on client and other receivables	12	67
Other, net	15	10
Changes in operating assets and liabilities:
Investments segregated and on deposit for regulatory purposes	535	750
Receivable from brokers, dealers and clearing organizations	(406)	(238)
Receivable from clients, net	1,758	(5,224)
Receivable from/payable to affiliates, net	(18)	(98)
Other receivables, net	43	(91)
Securities owned, at fair value	(162)	308
Other assets	(19)	(28)
Payable to brokers, dealers and clearing organizations	230	1,012
Payable to clients	1,704	(2,553)
Accounts payable and other liabilities	223	(159)
Net cash provided by (used in) operating activities	5,773	(5,000)
Cash flows from investing activities:
Purchase of property and equipment	(151)	(166)
Proceeds from sale of property and equipment	0	12
Cash received from business-related divestiture	62	0
Cash paid in business acquisition	0	(4)
Purchase of investments available-for-sale, at fair value	(899)	(392)
Proceeds from sale of investments available-for-sale, at fair value	299	643
Purchase of short-term investments	(1)	(1)
Proceeds from sale and maturity of short-term investments	1	66
Other, net	20	0
Net cash provided by (used in) investing activities	(669)	158
Cash flows from financing activities:
Proceeds from issuance of long-term debt	999	0
Payment of debt issuance costs	(8)	(3)
Net payments on securities sold under agreements to repurchase	(96)	0
Proceeds from senior revolving credit facilities	1,700	2,900
Principal payments on senior revolving credit facilities	(1,700)	(2,900)
Payment of cash dividends	(503)	(357)
Purchase of treasury stock	(673)	0
Purchase of treasury stock for income tax withholding on stock-based compensation	(12)	(16)
Payment for future treasury stock purchases under accelerated stock repurchase agreement	(74)	0
Other	0	2
Net cash used in financing activities	(367)	(374)
Net increase (decrease) in cash, cash equivalents, restricted cash and restricted cash equivalents	4,737	(5,216)
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	4,548	9,760
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period	9,285	4,544
Supplemental cash flow information:
Interest paid	112	88
Income taxes paid	$ 226	$ 278

Basis of Presentation

Basis of Presentation	9 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements include the accounts of TD Ameritrade Holding Corporation (the "Parent") and its wholly-owned subsidiaries (collectively, the "Company"). Intercompany balances and transactions have been eliminated. On June 28, 2019, pursuant to an Asset Purchase Agreement, TD Ameritrade Trust Company ("TDATC"), an indirect wholly-owned subsidiary of the Company, sold its retirement plan custody and trust assets. The sale of the retirement plan custody and trust assets resulted in a $60 million gain, which is included in gain on business-related divestiture on the Condensed Consolidated Statements of Income. These financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC") and, in the opinion of management, reflect all adjustments, which are all of a normal recurring nature, necessary to present fairly the financial position, results of operations and cash flows for the periods presented in conformity with U.S. generally accepted accounting principles ("GAAP"). These financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company's annual report filed on Form 10-K for the fiscal year ended September 30, 2018 . Recently Adopted Accounting Pronouncements ASU 2016-18 — On October 1, 2018, the Company adopted Accounting Standards Update ("ASU") 2016-18, Restricted Cash , using a retrospective transition method to each period presented. This ASU amends the guidance in Accounting Standards Codification ("ASC") Topic 230, Statement of Cash Flows , and is intended to reduce the diversity in the classification and presentation of changes in restricted cash on the statement of cash flows. The amendments within this ASU require that the reconciliation of the beginning-of-period and end-of-period cash and cash equivalents amounts shown on the statement of cash flows include restricted cash and restricted cash equivalents. If restricted cash and restricted cash equivalents are presented separately from cash and cash equivalents on the balance sheet, an entity is required to reconcile the amounts presented on the statement of cash flows to the amounts on the balance sheet. An entity is also required to disclose information regarding the nature of the restrictions. Under the retrospective transition method, the Company recorded a decrease of $5.1 billion in cash flows from operating activities for the nine months ended June 30, 2018 to reflect the reclassification of changes in restricted cash and restricted cash equivalents amounts from the operating section to the beginning-of-period and end-of-period cash, cash equivalents, restricted cash and restricted cash equivalents amounts within the Condensed Consolidated Statements of Cash Flows. See Note 2 for additional information regarding restricted cash and restricted cash equivalents. ASU 2016-16 — On October 1, 2018, the Company adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. This ASU amends the guidance in ASC Topic 740, Income Taxes . The amendments in this ASU are intended to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory by requiring an entity to recognize the income tax consequences when a transfer occurs, instead of when the asset is sold to a third party. The adoption of ASU 2016-16 did not have an impact on the Company's condensed consolidated financial statements. ASU 2014-09 — On October 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers , using a modified retrospective approach, which requires the standard be applied only to the most current period presented, with the cumulative effect of initially applying the standard recognized at the date of initial application. The new revenue recognition standard is intended to clarify the principles of recognizing revenue from contracts with customers and to improve financial reporting by creating common revenue recognition guidance for U.S. GAAP and International Financial Reporting Standards. This ASU supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition, and most industry-specific guidance. Entities are required to apply the following steps when recognizing revenue under ASU 2014-09: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This ASU also requires additional disclosures related to the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. The adoption of this standard did not have a material impact on the Company's financial condition, results of operations or cash flows, as the satisfaction of performance obligations under the new guidance is materially consistent with the Company's previous revenue recognition policies. However, the adoption of this standard did impact the Company by: (1) requiring the capitalization of sales commissions paid to employees for obtaining new contracts with clients and (2) accounting for revenues from certain contracts on a gross basis when the Company is acting as a principal, as compared to the prior guidance, which allowed for these contracts to be accounted for on a net basis. For additional information on the Company's adoption of the amended guidance, see Note 16 , Revenue Recognition. The new guidance does not apply to revenue associated with financial instruments, such as interest revenue, which is accounted for under other GAAP. Accordingly, net interest revenue was not impacted. Recently Issued Accounting Pronouncements ASU 2017-12 — In August 2017, the Financial Accounting Standards Board ("FASB") issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities , which will amend the guidance in ASC Topic 815, Derivatives and Hedging. The objective of this ASU is to improve the financial reporting of hedging relationships to better portray the economic results of an entity's risk management activities in its financial statements through changes to both the designation and measurement guidance for qualifying hedging relationships and to the presentation of hedge results. In addition, the amendments in this ASU make certain targeted improvements that are intended to simplify the application of the hedge accounting guidance in current GAAP. All transition requirements and elections under ASU 2017-12 should be applied to hedging relationships existing on the date of adoption, with the effect of the adoption reflected as of the beginning of the fiscal year of adoption. The amended presentation and disclosure guidance is required only prospectively. Subsequent to issuing ASU 2017-12, the FASB has issued additional standards for the purpose of providing codification improvements as well as introducing an additional benchmark interest rate (SOFR) for hedge accounting purposes. SOFR is a volume-weighted median interest rate that is calculated daily based on overnight transactions from the prior day's trading activity in specified segments of the U.S. Treasury repo market. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2017-12. ASU 2017-12 will be effective for the Company's fiscal year beginning October 1, 2019, with early adoption permitted. The Company does not expect this ASU to have a material impact on its condensed consolidated financial statements. ASU 2016-13 — In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments . The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about an entity's expected credit losses on financial instruments and other commitments to extend credit at each reporting date. To achieve this objective, the amendments in this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to develop credit loss estimates. Subsequent to issuing ASU 2016-13, the FASB has issued additional standards for the purpose of clarifying certain aspects of ASU 2016-13, as well as providing codification improvements and targeted transition relief under the standard. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2016-13. ASU 2016-13 will be effective for the Company's fiscal year beginning October 1, 2020, using a modified retrospective approach. Early adoption is permitted. The Company is currently assessing the impact this ASU will have on its condensed consolidated financial statements. ASU 2016-02 — In February 2016, the FASB issued ASU 2016-02, Leases . This ASU will supersede the guidance in ASC Topic 840, Leases . Under ASU 2016-02, for lease arrangements exceeding a 12-month term, a lessee will be required to recognize in the balance sheet a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. ASU 2016-02 will retain a distinction between finance and operating leases; however, the principal difference between the previous guidance and the new guidance is that lease assets and liabilities arising from operating leases will be recognized in the balance sheet under the new guidance. The recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee will not significantly change from current GAAP. The accounting applied by a lessor will be largely unchanged from that applied under current GAAP. Subsequent to issuing ASU 2016-02, the FASB has issued additional standards for the purpose of clarifying certain aspects of ASU 2016-02 and providing an additional (optional) transition method with which to adopt the new leases standard. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2016-02. Under ASU 2016-02, an entity may apply the amendments by using one of the following two methods: (1) recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach or (2) apply the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company plans to adopt the new lease accounting guidance on October 1, 2019 by applying the standard at the adoption date and recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company does not expect this guidance to have a material impact on its earnings per share (EPS); however, upon the adoption of the lease standard, the Company will recognize a right-of-use asset and a lease liability on the Condensed Consolidated Balance Sheet, primarily related to leases of its retail branch offices and administrative and operational facilities. Based upon the Company's current lease portfolio, the initial recognition and measurement of the right-of-use asset and lease liability are each expected to be approximately 1% of the Company's total assets and will be primarily based on the present value of the Company's remaining operating lease payments. The Company is in the process of refining its methodology to estimate the right-of-use asset and lease liability, testing software updates and finalizing the internal control structure that will support these accounting changes.

Cash, Cash Equivalents, Restric

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	9 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents The Company's cash and cash equivalents is summarized in the following table (dollars in millions): June 30, September 30, Broker-dealer subsidiaries $ 1,715 $ 2,094 Corporate 931 342 Trust company subsidiary 202 124 Futures commission merchant and forex dealer member subsidiary 87 89 Investment advisory subsidiaries 18 41 Total cash and cash equivalents $ 2,953 $ 2,690 Capital requirements may limit the amount of cash available for dividend from the broker-dealer, trust company and futures commission merchant ("FCM")/forex dealer member ("FDM") subsidiaries to the Parent. The following table provides a reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents reported within the Condensed Consolidated Balance Sheets to the total of the same amounts shown in the Condensed Consolidated Statements of Cash Flows (dollars in millions): June 30, September 30, Cash and cash equivalents $ 2,953 $ 2,690 Restricted cash and restricted cash equivalents included in cash and investments segregated and on deposit for regulatory purposes 6,332 1,858 Total cash, cash equivalents, restricted cash and restricted cash equivalents shown in the Condensed Consolidated Statements of Cash Flows $ 9,285 $ 4,548 Amounts included in restricted cash and restricted cash equivalents consist primarily of qualified deposits in special reserve bank accounts for the exclusive benefit of clients under Rule 15c3-3 of the Securities Exchange Act of 1934 (the "Exchange Act") and other regulations.

Cash and Investments Segregated

Cash and Investments Segregated and on Deposit for Regulatory Purposes	9 Months Ended
	Jun. 30, 2019
Restricted Cash and Investments [Abstract]
Cash and Investments Segregated and on Deposit for Regulatory Purposes	Cash and Investments Segregated and on Deposit for Regulatory Purposes Cash and investments segregated and on deposit for regulatory purposes consists of the following (dollars in millions): June 30, September 30, Cash in demand deposit accounts $ 2,861 $ 956 U.S. government debt securities 2,822 200 U.S. government agency mortgage-backed securities 767 1,302 Reverse repurchase agreements (collateralized by U.S. government debt securities) 500 500 Cash on deposit with futures commission merchants 149 202 U.S. government debt securities on deposit with futures commission merchant 25 25 Total $ 7,124 $ 3,185

Investments Available-for-Sale

Investments Available-for-Sale (Notes)	9 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investments Available-for-Sale	Investments Available-for-Sale The following tables present the amortized cost and fair value of available-for-sale securities (dollars in millions): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: U.S. Treasury securities $ 1,096 $ 33 $ — $ 1,129 September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: U.S. Treasury securities $ 493 $ — $ (9 ) $ 484 As of September 30, 2018, the Company had pledged $98 million of available-for-sale securities as collateral for repurchase agreements. The following table presents the contractual maturities of available-for-sale securities as of June 30, 2019 (dollars in millions): Amortized Cost Fair Value Available-for-sale U.S. Treasury securities: Due within one to five years $ 384 $ 407 Due within five to ten years 712 722 Total available-for-sale U.S. Treasury securities $ 1,096 $ 1,129

Exit Liabilities

Exit Liabilities	9 Months Ended
	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Exit Liabilities	Exit Liabilities As of September 18, 2017, the date the Company completed its acquisition of Scottrade Financial Services, Inc. ("Scottrade"), the Company began to incur costs in connection with actions taken to attain synergies from combining the operations of the Company and Scottrade. These costs, collectively referred to as "acquisition-related exit costs," include severance and other costs associated with consolidating facilities and administrative functions. As of September 30, 2018, substantially all of the acquisition-related exit costs had been incurred. The following tables summarize activity in the Company's exit liabilities for the three and nine month periods ended June 30, 2019 and 2018 , which are included in accounts payable and other liabilities on the Condensed Consolidated Balance Sheets (dollars in millions): Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, March 31, 2019 $ 5 $ 3 $ 8 Costs incurred and charged to expense 2 (1) — 2 Costs paid or otherwise settled (2 ) — (2 ) Balance, June 30, 2019 $ 5 $ 3 $ 8 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, March 31, 2018 $ 113 $ 38 $ 151 Costs incurred and charged to expense 31 (1) 17 (2) 48 Costs paid or otherwise settled (106 ) (24 ) (130 ) Balance, June 30, 2018 $ 38 $ 31 $ 69 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, September 30, 2018 $ 21 $ 48 $ 69 Costs incurred and charged to expense 6 (1) (2 ) (2) 4 Costs paid or otherwise settled (22 ) (43 ) (65 ) Balance, June 30, 2019 $ 5 $ 3 $ 8 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, September 30, 2017 $ 138 $ — $ 138 Exit liabilities assumed - post closing adjustments — 9 9 Costs incurred and charged to expense 209 (1) 178 (2) 387 Costs paid or otherwise settled (309 ) (156 ) (465 ) Balance, June 30, 2018 $ 38 $ 31 $ 69 (1) Costs incurred for severance pay and other employment benefits are included in employee compensation and benefits on the Condensed Consolidated Statements of Income. (2) Costs incurred for contract termination and other costs are primarily included in other operating expense and professional services on the Condensed Consolidated Statements of Income. The following table summarizes the cumulative amount of acquisition-related exit costs incurred by the Company related to the Scottrade acquisition as of June 30, 2019 (dollars in millions): Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Exit liabilities assumed in business acquisition $ 100 $ 9 $ 109 Employee compensation and benefits 267 — 267 Clearing and execution costs — 1 1 Communications — 1 1 Occupancy and equipment costs — 7 7 Professional services — 30 30 Other operating expense — 171 171 Other non-operating expense — 2 2 Total $ 367 $ 221 $ 588

Income Taxes

Income Taxes	9 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's effective income tax rate for the nine months ended June 30, 2019 and 2018 was 24.2% and 20.3% , respectively. The provision for income taxes for the nine months ended June 30, 2019 included $18 million of favorable adjustments related to state income tax matters and a $3 million income tax benefit resulting from the vesting of equity-based compensation. These items had a favorable impact on the Company's earnings for the nine months ended June 30, 2019 of approximately $0.04 per share. The provision for income taxes for the nine months ended June 30, 2018 included a net favorable adjustment of $71 million related to the remeasurement of the Company's deferred income tax balances as it pertained to the Tax Cuts and Jobs Act (the "Act"), a $5 million income tax benefit resulting from the change in accounting for income taxes related to equity-based compensation under ASU 2016-09, $10 million of favorable resolutions of state income tax matters and a $21 million favorable benefit resulting from accelerating certain deductions, including acquisition-related exit costs, to leverage higher 2017 pre-enactment tax rates. The effective income tax rate was also impacted by a $9 million unfavorable remeasurement of uncertain tax positions related to certain federal incentives. The Act was enacted on December 22, 2017, reducing the U.S. federal corporate income tax rate from 35% to 21% . These items had a net favorable impact on the Company's earnings for the nine months ended June 30, 2018 of approximately $0.17 per share.

Long-term Debt and Other Borrow

Long-term Debt and Other Borrowings	9 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Long-term Debt and Other Borrowings	Long-term Debt and Other Borrowings Long-term debt and other borrowings consist of the following (dollars in millions): June 30, 2019 Face Value Unamortized Discounts and Debt Issuance Costs Fair Value Adjustment (1) Net Carrying Value Long-term debt: Senior Notes: 5.600% Notes due 2019 $ 500 $ — $ 2 $ 502 Variable-rate Notes due 2021 600 (3 ) — 597 2.950% Notes due 2022 750 (3 ) 4 751 3.75% Notes due 2024 400 (4 ) — 396 3.625% Notes due 2025 500 (3 ) 19 516 3.300% Notes due 2027 800 (8 ) 20 812 Total long-term debt $ 3,550 $ (21 ) $ 45 $ 3,574 September 30, 2018 Face Value Unamortized Discounts and Debt Issuance Costs Fair Value Adjustment (1) Net Carrying Value Other borrowings: Securities sold under agreements to repurchase $ 96 $ — $ — $ 96 Long-term debt: Senior Notes: 5.600% Notes due 2019 500 (1 ) 2 501 2.950% Notes due 2022 750 (4 ) (27 ) 719 3.625% Notes due 2025 500 (3 ) (17 ) 480 3.300% Notes due 2027 800 (9 ) (52 ) 739 Subtotal - Long-term debt 2,550 (17 ) (94 ) 2,439 Total long-term debt and other borrowings $ 2,646 $ (17 ) $ (94 ) $ 2,535 (1) Fair value adjustments relate to changes in the fair value of the debt while in a fair value hedging relationship. See " Fair Value Hedging " below. Fiscal year maturities on long-term debt outstanding at June 30, 2019 are as follows (dollars in millions): 2019 Remaining $ — 2020 500 2021 — 2022 1,350 2023 — Thereafter 1,700 Total $ 3,550 Senior Notes — As of June 30, 2019 , the Company had $3.55 billion aggregate principal amount of unsecured Senior Notes (together, the "Senior Notes"). On October 30, 2018, the Company sold, through a public offering, $600 million aggregate principal amount of unsecured variable-rate senior notes due November 1, 2021 (the "2021 Notes") and $400 million aggregate principal amount of unsecured 3.750% senior notes due April 1, 2024 (the "2024 Notes"). The Company intends to use the net proceeds from the issuance of the 2021 Notes and 2024 Notes for general corporate purposes, including to augment liquidity. The 2021 Notes bear interest at a variable rate, which resets quarterly and is equal to three-month LIBOR plus 0.430% per annum, payable quarterly on February 1, May 1, August 1 and November 1 of each year, beginning on February 1, 2019. Interest on the fixed-rate 2024 Notes will be payable in arrears semi-annually on April 1 and October 1 of each year, beginning on April 1, 2019. The Company's obligations in respect to the 2021 Notes and the 2024 Notes are not guaranteed by any of its subsidiaries. The Company may redeem the 2024 Notes, in whole or in part, at any time prior to March 2, 2024 at a redemption price equal to the greater of (a) 100% of the principal amount of the notes being redeemed, and (b) the sum of the present values of the remaining scheduled payments of principal and interest on the notes being redeemed, discounted to the date of redemption on a semi-annual basis at the comparable U.S. Treasury rate, plus 15 basis points, plus accrued and unpaid interest to the date of redemption. The Company may redeem the 2021 Notes and 2024 Notes, in whole or in part, at any time on or after October 2, 2021 and March 2, 2024, respectively, at a redemption price equal to 100% of the principal amount of the notes being redeemed, plus, in each case, accrued and unpaid interest to the date of redemption. Lines of Credit — TD Ameritrade Clearing, Inc. ("TDAC"), a clearing broker-dealer subsidiary of the Company, utilizes secured uncommitted lines of credit for short-term liquidity. Under these secured uncommitted lines, TDAC borrows on either a demand or short-term basis from two unaffiliated banks and pledges client margin securities as collateral. Advances under the secured uncommitted lines are dependent on TDAC having acceptable collateral as determined by each secured uncommitted credit agreement. At June 30, 2019 , the terms of the secured uncommitted credit agreements do not specify borrowing limits. The availability of TDAC's secured uncommitted lines is subject to approval by the individual banks each time an advance is requested and may be denied. There were no borrowings outstanding under the secured uncommitted lines of credit as of June 30, 2019 and September 30, 2018 . Securities Sold Under Agreements to Repurchase (repurchase agreements) — Under repurchase agreements, the Company receives cash from the counterparty and provides U.S. government debt securities as collateral. The Company's repurchase agreements generally mature between 30 and 90 days following the transaction date and are accounted for as secured borrowings. There were no borrowings outstanding under repurchase agreements as of June 30, 2019 . The remaining contractual maturities of the repurchase agreements with outstanding balances as of September 30, 2018 were less than 30 days. The weighted average interest rate on the balances outstanding as of September 30, 2018 was 2.35% . See "General Contingencies" in Note 9 for a discussion of the potential risks associated with repurchase agreements and how the Company mitigates those risks. Fair Value Hedging — The Company is exposed to changes in the fair value of its fixed-rate Senior Notes resulting from interest rate fluctuations. To hedge a vast majority of this exposure, the Company has entered into fixed-for-variable interest rate swaps on each of the 2019 Notes, 2022 Notes, 2025 Notes and 2027 Notes (together, the "Hedged Senior Notes"). Each fixed-for-variable interest rate swap has a notional amount and a maturity date matching the aggregate principal amount and maturity date, respectively, for each of the respective Hedged Senior Notes. The interest rate swaps effectively change the fixed-rate interest on the Hedged Senior Notes to variable-rate interest. Under the terms of the interest rate swap agreements, the Company receives semi-annual fixed-rate interest payments based on the same rates applicable to the Hedged Senior Notes, and makes quarterly variable-rate interest payments based on three-month LIBOR plus (a) 2.3745% for the swap on the 2019 Notes, (b) 0.9486% for the swap on the 2022 Notes, (c) 1.1022% for the swap on the 2025 Notes and (d) 1.0340% for the swap on the 2027 Notes. As of June 30, 2019 , the weighted average interest rate on the aggregate principal balance of the Senior Notes was 3.72% . The interest rate swaps are accounted for as fair value hedges and qualify for the shortcut method of accounting. Changes in the payment of interest resulting from the interest rate swaps are recorded in interest on borrowings on the Condensed Consolidated Statements of Income. Changes in fair value of the interest rate swaps are completely offset by changes in fair value of the related notes, resulting in no effect on net income. The following table summarizes gains and losses resulting from changes in the fair value of interest rate swaps designated as fair value hedges and the hedged fixed-rate debt for the periods indicated (dollars in millions): Three Months Ended June 30, Nine Months Ended June 30, 2019 2018 2019 2018 Gain (loss) on fair value of interest rate swaps $ 53 $ (21 ) $ 139 $ (100 ) Gain (loss) on fair value of hedged fixed-rate debt (53 ) 21 (139 ) 100 Net gain (loss) recorded in interest on borrowings $ — $ — $ — $ — Balance Sheet Impact of Hedging Instruments — The following table summarizes the classification and the fair value of outstanding derivatives designated as hedging instruments on the Condensed Consolidated Balance Sheets (dollars in millions): June 30, September 30, Pay-variable interest rate swaps designated as fair value hedges: Other assets $ 45 $ 2 Accounts payable and other liabilities $ — $ (96 ) The interest rate swaps are subject to counterparty credit risk. Credit risk is managed by limiting activity to approved counterparties that meet a minimum credit rating threshold, by entering into credit support agreements, or by utilizing approved central clearing counterparties registered with the Commodity Futures Trading Commission ("CFTC"). The interest rate swaps require daily collateral coverage, in the form of cash or U.S. Treasury securities, for the aggregate fair value of the interest rate swaps (including accrued interest). As of June 30, 2019 and September 30, 2018 , the pay-variable interest rate swap counterparties had pledged $45 million and $10 million of collateral, respectively, to the Company in the form of cash. A liability for collateral pledged to the Company in the form of cash is recorded in accounts payable and other liabilities on the Condensed Consolidated Balance Sheets. As of September 30, 2018 , the Company had pledged $82 million of collateral to the pay-variable interest rate swap counterparties in the form of cash. An asset for collateral pledged to the swap counterparties in the form of cash is recorded in other receivables on the Condensed Consolidated Balance Sheets. TD Ameritrade Holding Corporation Senior Revolving Credit Facility — On April 21, 2017, the Parent entered into a credit agreement consisting of a senior unsecured committed revolving credit facility in the aggregate principal amount of $300 million (the "Parent Revolving Facility"). The maturity date of the Parent Revolving Facility is April 21, 2022. The applicable interest rate under the Parent Revolving Facility is calculated as a per annum rate equal to, at the option of the Parent, (a) LIBOR plus an interest rate margin ("Parent Eurodollar loans") or (b) (i) the highest of (x) the prime rate, (y) the federal funds effective rate (or, if the federal funds effective rate is unavailable, the overnight bank funding rate) plus 0.50% or (z) the eurodollar rate assuming a one-month interest period plus 1.00% , plus (ii) an interest rate margin ("ABR loans"). The interest rate margin ranges from 0.875% to 1.50% for Parent Eurodollar loans and from 0% to 0.50% for ABR loans, determined by reference to the Company's public debt ratings. The Parent is obligated to pay a commitment fee ranging from 0.08% to 0.20% on any unused amount of the Parent Revolving Facility, determined by reference to the Company's public debt ratings. There were no borrowings outstanding under the Parent Revolving Facility as of June 30, 2019 and September 30, 2018. As of June 30, 2019, the interest rate margin would have been 1.125% for Parent Eurodollar loans and 0.125% for ABR loans, and the commitment fee was 0.125% , each determined by reference to the Company's public debt ratings. TD Ameritrade Clearing, Inc. Senior Revolving Credit Facilities — TDAC has access to two senior unsecured committed revolving credit facilities with an aggregate principal amount of $1.45 billion , consisting of a $600 million (the " $600 Million Revolving Facility") and an $850 million (the " $850 Million Revolving Facility") senior revolving facility (together, the "TDAC Revolving Facilities"). TDAC entered into the $850 Million Revolving Facility on May 16, 2019, replacing its prior $850 million senior unsecured committed revolving credit facility, which matured on the same date. The maturity dates of the $600 Million Revolving Facility and the $850 Million Revolving Facility are April 21, 2022 and May 14, 2020, respectively. The applicable interest rate under each of the TDAC Revolving Facilities is calculated as a per annum rate equal to, at the option of TDAC, (a) LIBOR plus an interest rate margin ("TDAC Eurodollar loans") or (b) the federal funds effective rate plus an interest rate margin ("Federal Funds Rate loans"). The interest rate margin ranges from 0.75% to 1.25% for both TDAC Eurodollar loans and Federal Funds Rate loans, determined by reference to the Company's public debt ratings. TDAC is obligated to pay commitment fees ranging from 0.07% to 0.175% and from 0.06% to 0.125% on any unused amounts of the $600 Million Revolving Facility and the $850 Million Revolving Facility, respectively, each determined by reference to the Company's public debt ratings. There were no borrowings outstanding under the TDAC Revolving Facilities as of June 30, 2019 and September 30, 2018. As of June 30, 2019, the interest rate margin under the TDAC Revolving Facilities would have been 1.00% for both TDAC Eurodollar loans and Federal Funds Rate loans, determined by reference to the Company's public debt ratings. As of June 30, 2019, the commitment fees under the $600 Million Revolving Facility and the $850 Million Revolving Facility were 0.10% and 0.08% , respectively, each determined by reference to the Company's public debt ratings. The $850 Million Revolving Facility contains negative covenants that limit or restrict, subject to certain exceptions, the incurrence of liens, indebtedness of TDAC, change in nature of business, mergers, consolidations, and the sale of all or substantially all of the assets of TDAC. TDAC is also required to maintain minimum consolidated tangible net worth and is required to maintain compliance with minimum regulatory net capital requirements. TDAC was in compliance with all covenants under the $850 Million Revolving Facility as of June 30, 2019. Intercompany Credit Agreements — The Parent has entered into credit agreements with each of its primary broker-dealer and FCM/FDM subsidiaries, under which the Parent may make loans of cash or securities under committed and/or uncommitted lines of credit. Key information about the committed and/or uncommitted lines of credit is summarized in the following table (dollars in millions): Borrower Subsidiary Committed Facility Uncommitted Facility (1) Termination Date TD Ameritrade Clearing, Inc. $1,200 $300 March 1, 2022 TD Ameritrade, Inc. N/A $300 March 1, 2022 TD Ameritrade Futures & Forex LLC $45 N/A August 11, 2021 (1) The Parent is permitted, but under no obligation, to make loans under uncommitted facilities. Loans under both the committed and uncommitted facilities bear interest at the same rate as borrowings under the TDAC Revolving Facilities and must be repaid with interest on or before the termination date. There were no borrowings outstanding under any of the intercompany credit agreements as of June 30, 2019 and September 30, 2018 .

Capital Requirements

Capital Requirements	9 Months Ended
	Jun. 30, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Capital Requirements	Capital Requirements The Company's broker-dealer subsidiaries are subject to the SEC Uniform Net Capital Rule (Rule 15c3-1 under the Exchange Act), administered by the SEC and the Financial Industry Regulatory Authority ("FINRA"), which requires the maintenance of minimum net capital, as defined. Net capital and the related net capital requirement may fluctuate on a daily basis. TDAC, the Company's clearing broker-dealer subsidiary, and TD Ameritrade, Inc., an introducing broker-dealer subsidiary of the Company, compute net capital under the alternative method as permitted by Rule 15c3-1. TDAC is required to maintain minimum net capital of the greater of $1.5 million , which is based on the type of business conducted by the broker-dealer, or 2% of aggregate debit balances arising from client transactions. TD Ameritrade, Inc. is required to maintain minimum net capital of the greater of $250,000 or 2% of aggregate debit balances arising from client transactions. In addition, under the alternative method, a broker-dealer may not repay any subordinated borrowings, pay cash dividends or make any unsecured advances or loans to its parent company or employees if such payment would result in net capital of less than (a) 5% of aggregate debit balances or (b) 120% of its minimum dollar requirement. TD Ameritrade Futures & Forex LLC ("TDAFF"), the Company's FCM and FDM subsidiary registered with the CFTC, is subject to CFTC Regulations 1.17 and 5.7 under the Commodity Exchange Act, administered by the CFTC and the National Futures Association ("NFA"). As an FCM, TDAFF is required to maintain minimum adjusted net capital under CFTC Regulation 1.17 of the greater of (a) $1.0 million or (b) its futures risk-based capital requirement, equal to 8% of the total risk margin requirement for all futures positions carried by the FCM in client and nonclient accounts. As an FDM, TDAFF is also subject to the net capital requirements under CFTC Regulation 5.7, which requires TDAFF to maintain minimum adjusted net capital of the greater of (a) any amount required under CFTC Regulation 1.17 as described above or (b) $20.0 million plus 5% of all foreign exchange liabilities owed to forex clients in excess of $10.0 million . In addition, an FCM and FDM must provide notice to the CFTC if its adjusted net capital amounts to less than (a) 110% of its risk-based capital requirement under CFTC Regulation 1.17, (b) 150% of its $1.0 million minimum dollar requirement, or (c) 110% of $20.0 million plus 5% of all foreign exchange liabilities owed to forex clients in excess of $10.0 million . Net capital and net capital requirements for the Company's broker-dealer subsidiaries are summarized in the following tables (dollars in millions): TD Ameritrade Clearing, Inc. Date Net Capital Required Net Capital (2% of Aggregate Debit Balances) Net Capital in Excess of Required Net Capital Ratio of Net Capital to Aggregate Debit Balances June 30, 2019 $ 2,980 $ 479 $ 2,501 12.44 % September 30, 2018 $ 2,831 $ 525 $ 2,306 10.79 % TD Ameritrade, Inc. Date Net Capital Required Net Capital (Minimum Dollar Requirement) Net Capital in Excess of Required Net Capital June 30, 2019 $ 218 $ 0.25 $ 218 September 30, 2018 $ 181 $ 0.25 $ 181 Adjusted net capital and adjusted net capital requirements for the Company's FCM and FDM subsidiary are summarized in the following table (dollars in millions): TD Ameritrade Futures & Forex LLC Date Adjusted Net Capital Required Adjusted Net Capital ($20 Million Plus 5% of All Foreign Exchange Liabilities Owed to Forex Clients in Excess of $10 Million) Adjusted Net Capital in Excess of Required Adjusted Net Capital June 30, 2019 $ 130 $ 23 $ 107 September 30, 2018 $ 129 $ 23 $ 106 The Company's non-depository trust company subsidiary, TD Ameritrade Trust Company ("TDATC"), is subject to capital requirements established by the State of Maine, which require TDATC to maintain minimum Tier 1 capital. TDATC's Tier 1 capital was $88 million and $39 million as of June 30, 2019 and September 30, 2018 , respectively, which exceeded the required Tier 1 capital by $67 million and $18 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal and Regulatory Matters Order Routing Matters — In 2014, five putative class action complaints were filed regarding TD Ameritrade, Inc.'s routing of client orders and one putative class action was filed regarding Scottrade, Inc.'s routing of client orders. Five of the six cases were dismissed and the United States Court of Appeals, 8th Circuit, affirmed the dismissals in those cases that were appealed. The one remaining case is Roderick Ford (replacing Gerald Klein ) v. TD Ameritrade Holding Corporation, et al., Case No. 8:14CV396 (U.S. District Court, District of Nebraska). In the remaining case, plaintiff alleges that, when routing client orders to various market centers, defendants did not seek best execution, and instead routed clients' orders to market venues that paid TD Ameritrade, Inc. the most money for order flow. Plaintiff alleges that defendants made misrepresentations and omissions regarding the Company's order routing practices. The complaint asserts claims of violations of Section 10(b) and 20 of the Exchange Act and SEC Rule 10b-5. The complaint seeks damages, injunctive relief, and other relief. Plaintiff filed a motion for class certification, which defendants opposed. On July 12, 2018, the Magistrate Judge issued findings and a recommendation that plaintiff's motion for class certification be denied. Plaintiff filed objections to the Magistrate Judge's findings and recommendation, which defendants opposed. On September 14, 2018, the District Judge sustained plaintiff's objections, rejected the Magistrate Judge's recommendation and granted plaintiff's motion for class certification. On September 28, 2018, defendants filed a petition requesting that the U.S. Court of Appeals, 8th Circuit, grant an immediate appeal of the District Court's class certification decision. The U.S. Court of Appeals, 8th Circuit, granted defendants' petition on December 18, 2018. Briefing on the appeal is complete. The Securities Industry and Financial Markets Association and the U.S. Chamber of Commerce have filed amicus curiae briefs in support of the Company's appeal. The Company intends to vigorously defend against this lawsuit and is unable to predict the outcome or the timing of the ultimate resolution of the lawsuit, or the potential loss, if any, that may result. Certain regulatory authorities are conducting examinations and investigations regarding the routing of client orders. TD Ameritrade, Inc., TDAC and Scottrade, Inc. have received requests for documents and information from the regulatory authorities. TD Ameritrade, Inc., TDAC and Scottrade, Inc. are cooperating with the requests. Aequitas Securities Litigation — An amended putative class action complaint was filed in the U.S. District Court for the District of Oregon in Lawrence Ciuffitelli et al. v. Deloitte & Touche LLP, EisnerAmper LLP, Sidley Austin LLP, Tonkon Torp LLP, TD Ameritrade, Inc., and Integrity Bank & Trust, Case No. 3:16CV580, on May 19, 2016. A second amended putative class action complaint was filed on September 8, 2017, in which Duff & Phelps was added as a defendant. The putative class includes all persons who purchased securities of Aequitas Commercial Finance, LLC and its affiliates on or after June 9, 2010. Other groups of plaintiffs have filed non-class action lawsuits in Oregon Circuit Court, Multnomah County, against these and other defendants: Walter Wurster, et al. v. Deloitte & Touche et al. , Case No. 16CV25920 (filed Aug. 11, 2016), Kenneth Pommier, et al. v. Deloitte & Touche et al., Case No. 16CV36439 (filed Nov. 3, 2016), Charles Ramsdell, et al. v. Deloitte & Touche et al., Case No. 16CV40659 (filed Dec. 2, 2016), Charles Layton, et al. v. Deloitte & Touche et al., Case No. 17CV42915 (filed October 2, 2017) and John Cavanagh, et al. v. Deloitte & Touche et al. , Case No. 18CV09052 (filed March 7, 2018). FINRA arbitrations have also been filed against TD Ameritrade, Inc. The claims in these actions include allegations that the sales of Aequitas securities were unlawful, the defendants participated and materially aided in such sales in violation of the Oregon securities laws, and material misstatements and omissions were made. While the factual allegations differ in various respects among the cases, plaintiffs' allegations include assertions that: TD Ameritrade, Inc. customers purchased more than $140 million of Aequitas securities; TD Ameritrade, Inc. served as custodian for Aequitas securities; recommended and referred investors to financial advisors as part of its advisor referral program for the purpose of purchasing Aequitas securities; participated in marketing the securities; recommended the securities; provided assurances to investors about the safety of the securities; and developed a market for the securities. In the Ciuffitelli putative class action, plaintiffs allege that more than 1,500 investors were owed more than $600 million on the Aequitas securities they purchased. On August 1, 2018, the Magistrate Judge in that case issued findings and a recommendation that defendants' motions to dismiss the pending complaint be denied with limited exceptions not applicable to the Company. TD Ameritrade, Inc. and other defendants filed objections to the Magistrate Judge's findings and recommendation, which plaintiffs opposed. On September 24, 2018, the District Judge issued an opinion and order adopting the Magistrate Judge's findings and recommendation. In the non-class action lawsuits, approximately 200 named plaintiffs collectively allege a total of approximately $150 million in losses plus other damages. In the Wurster and Pommier cases, the Court, on TD Ameritrade Inc.'s motion, dismissed the claims by those plaintiffs who were TD Ameritrade, Inc. customers, in favor of arbitration. Twenty-nine of those plaintiffs filed claims in a FINRA arbitration on March 13, 2019. The Court in the Wurster and Pommier cases denied TD Ameritrade's motion to dismiss the claims by the plaintiffs who were not TD Ameritrade customers. Plaintiffs in the Ramsdell case have filed a second amended complaint in which TD Ameritrade, Inc. is not named as a defendant. On September 24, 2018, plaintiffs in the Cavanagh case dismissed their claims against TD Ameritrade, Inc. In May 2019, TD Ameritrade settled all of the pending non-class action claims for an immaterial amount paid by its insurers. Plaintiffs and defendants Tonkon Torp and Integrity Bank entered into agreements to settle the claims in the Ciuffitelli case on a class basis for an aggregate amount of $14.6 million subject to Court approval. Following a mediation, on July 9, 2019, plaintiffs and the remaining defendants in the Ciuffitelli case reached an agreement to settle the claims on a class basis for $220 million subject to Court approval. If the Court approves the settlement, TD Ameritrade will contribute $20 million and its insurers $12 million of the aggregate settlement amount. On July 15, 2019, the Magistrate Judge issued findings and a recommendation that the District Judge preliminarily approve the class settlements, and scheduled a settlement hearing for November 26, 2019. The Company is unable to predict the outcome or the timing of the ultimate resolution of this litigation, or the potential losses, if any, that may result. Other Legal and Regulatory Matters — The Company is subject to a number of other lawsuits, arbitrations, claims and other legal proceedings in connection with its business. Some of these legal actions include claims for substantial or unspecified compensatory and/or punitive damages. In addition, in the normal course of business, the Company discusses matters with its regulators raised during regulatory examinations or otherwise subject to their inquiry. These matters could result in censures, fines, penalties or other sanctions. ASC 450, Loss Contingencies, governs the recognition and disclosure of loss contingencies, including potential losses from legal and regulatory matters. ASC 450 categorizes loss contingencies using three terms based on the likelihood of occurrence of events that result in a loss: "probable" means that "the future event or events are likely to occur;" "remote" means that "the chance of the future event or events occurring is slight;" and "reasonably possible" means that "the chance of the future event or events occurring is more than remote but less than likely." Under ASC 450, the Company accrues for losses that are considered both probable and reasonably estimable. The Company may incur losses in addition to the amounts accrued where the losses are greater than estimated by management, or for matters for which an unfavorable outcome is considered reasonably possible, but not probable. The Company estimates that the aggregate range of reasonably possible losses in excess of amounts accrued is from $0 to $65 million as of June 30, 2019 . This estimated aggregate range of reasonably possible losses is based upon currently available information for those legal and regulatory matters in which the Company is involved, taking into account the Company's best estimate of reasonably possible losses for those matters as to which an estimate can be made. For certain matters, the Company does not believe an estimate can currently be made, as some matters are in preliminary stages and some matters have no specific amounts claimed. The Company's estimate involves significant judgment, given the varying stages of the proceedings and the inherent uncertainty of predicting outcomes. The estimated range will change from time to time as the underlying matters, stages of proceedings and available information change. Actual losses may vary significantly from the current estimated range. The Company believes, based on its current knowledge and after consultation with counsel, that the ultimate disposition of these legal and regulatory matters, individually or in the aggregate, is not likely to have a material adverse effect on the financial condition or cash flows of the Company. However, in light of the uncertainties involved in such matters, the Company is unable to predict the timing or the ultimate resolution of these matters, or the potential losses, fines, penalties or equitable relief, if any, that may result, and it is possible that the ultimate resolution of one or more of these matters may be material to the Company's results of operations for a particular reporting period. Income Taxes The Company's federal and state income tax returns are subject to examination by taxing authorities. Because the application of tax laws and regulations to many types of transactions is subject to varying interpretations, amounts reported in the condensed consolidated financial statements could be significantly changed at a later date upon final determinations by taxing authorities. General Contingencies In the ordinary course of business, there are various contingencies that are not reflected in the condensed consolidated financial statements. These include the Company's broker-dealer and FCM/FDM subsidiaries' client activities involving the execution, settlement and financing of various client securities, options, futures and foreign exchange transactions. These activities may expose the Company to credit risk and losses in the event the clients are unable to fulfill their contractual obligations. The Company extends margin credit and leverage to its clients. In margin transactions, the Company extends credit to the client, subject to various regulatory and internal margin requirements, collateralized by cash and securities in the client's account. In connection with these activities, the Company also routes client orders for execution and clears client transactions involving the sale of securities not yet purchased ("short sales"). Such margin-related transactions may expose the Company to credit risk in the event a client's assets are not sufficient to fully cover losses that the client may incur. Leverage involves securing a large potential future obligation with a lesser amount of collateral. The risks associated with margin credit and leverage increase during periods of rapid market movements, or in cases where leverage or collateral is concentrated and market movements occur. In the event the client fails to satisfy its obligations, the Company has the authority to liquidate certain positions in the client's account(s) at prevailing market prices in order to fulfill the client's obligations. However, during periods of rapid market movements, clients who utilize margin credit or leverage and who have collateralized their obligations with securities may find that the securities have a rapidly depreciating value (or increasing value with respect to short positions) and may not be sufficient to cover their obligations in the event of liquidation. The Company seeks to mitigate the risks associated with its client margin and leverage activities by requiring clients to maintain margin collateral in compliance with various regulatory and internal guidelines. The Company monitors required margin levels throughout each trading day and, pursuant to such guidelines, requires clients to deposit additional collateral, or to reduce positions, when necessary. The Company contracts with unaffiliated FCM, FDM and broker-dealer entities to clear and execute futures, options on futures and foreign exchange transactions for its clients. This can result in concentrations of credit risk with one or more of these counterparties. This risk is partially mitigated by the counterparties' obligation to comply with rules and regulations governing FCMs, FDMs and broker-dealers in the United States. These rules generally require maintenance of net capital and segregation of client funds and securities. In addition, the Company manages this risk by requiring credit approvals for counterparties and by utilizing account funding and sweep arrangement agreements that generally specify that all client cash in excess of futures funding requirements be transferred back to the clients' securities brokerage accounts at the Company on a daily basis. The Company loans securities temporarily to other broker-dealers in connection with its broker-dealer business. The Company receives cash as collateral for the securities loaned. Increases in securities prices may cause the market value of the securities loaned to exceed the amount of cash received as collateral. In the event the counterparty to these transactions does not return the loaned securities, the Company may be exposed to the risk of acquiring the securities at higher prevailing market prices in order to satisfy its client obligations. The Company mitigates this risk by requiring credit approvals for counterparties, by monitoring the market value of securities loaned on a daily basis and requiring additional cash as collateral when necessary, and by participating in a risk-sharing program offered through the Options Clearing Corporation ("OCC"). The Company borrows securities temporarily from other broker-dealers in connection with its broker-dealer business. The Company deposits cash as collateral for the securities borrowed. Decreases in securities prices may cause the market value of the securities borrowed to fall below the amount of cash deposited as collateral. In the event the counterparty to these transactions does not return the cash deposited, the Company may be exposed to the risk of selling the securities at prevailing market prices. The Company mitigates this risk by requiring credit approvals for counterparties, by monitoring the collateral values on a daily basis and requiring collateral to be returned by the counterparties when necessary, and by participating in a risk-sharing program offered through the OCC. The Company transacts in reverse repurchase agreements (securities purchased under agreements to resell) in connection with its broker-dealer business. The Company's policy is to take possession or control of securities with a market value in excess of the principal amount loaned, plus accrued interest, in order to collateralize resale agreements. The Company monitors the market value of the underlying securities that collateralize the related receivable on resale agreements on a daily basis and may require additional collateral when deemed appropriate. The Company utilizes securities sold under agreements to repurchase (repurchase agreements) to finance its short-term liquidity and capital needs. Under these agreements, the Company receives cash from the counterparties and provides U.S. Treasury securities as collateral, allowing the counterparties the right to sell or repledge the collateral. These agreements expose the Company to credit losses in the event the counterparties cannot meet their obligations. The Company mitigates this risk by requiring credit approvals for counterparties, by monitoring the market value of pledged securities owned on a daily basis and requiring the counterparties to return cash or excess collateral pledged when necessary. The Company has accepted collateral in connection with client margin loans and securities borrowed. Under applicable agreements, the Company is generally permitted to repledge securities held as collateral and use them to enter into securities lending arrangements. The following table summarizes the fair values of client margin securities and stock borrowings that were available to the Company to utilize as collateral on various borrowings or for other purposes, and the amount of that collateral loaned or repledged by the Company (dollars in billions): June 30, September 30, Client margin securities $ 29.0 $ 31.4 Stock borrowings 1.3 0.8 Total collateral available $ 30.3 $ 32.2 Collateral loaned $ 3.1 $ 2.9 Collateral repledged 4.1 6.3 Total collateral loaned or repledged $ 7.2 $ 9.2 The Company is subject to cash deposit and collateral requirements with clearinghouses based on its clients' trading activity. The following table summarizes cash deposited with and securities pledged to clearinghouses by the Company (dollars in millions): Assets Condensed Consolidated Balance Sheet Classification June 30, September 30, Cash Receivable from brokers, dealers and clearing organizations $ 461 $ 545 U.S. government debt securities Securities owned, at fair value 163 50 Total $ 624 $ 595 The Company manages its sweep program through off-balance sheet arrangements with The Toronto-Dominion Bank ("TD") and unaffiliated third-party depository financial institutions (together, the "Sweep Program Counterparties"). The sweep program is offered to eligible clients whereby the client's uninvested cash is swept into FDIC-insured (up to specified limits) money market deposit accounts at the Sweep Program Counterparties. The Company earns revenue on client cash at the Sweep Program Counterparties based on the return of floating-rate and fixed-rate notional investments. The Company designates amounts and maturity dates for the fixed-rate notional investments within the sweep program portfolios, subject to certain limitations. In the event the Company instructs the Sweep Program Counterparties to withdraw a fixed-rate notional investment prior to its maturity, the Company may be required to reimburse the Sweep Program Counterparties for any losses incurred as a result of the early withdrawal. In order to mitigate the risk of potential loss due to an early withdrawal of fixed-rate notional investments, the Company maintains a certain level of short-term floating-rate investments within the sweep program portfolios to meet client cash demands. See " Insured Deposit Account Agreement " in Note 14 for a description of the sweep arrangement between the Company and TD. Guarantees The Company is a member of and provides guarantees to securities clearinghouses and exchanges in connection with client trading activities. Under related agreements, the Company is generally required to guarantee the performance of other members. Under these agreements, if a member becomes unable to satisfy its obligations to the clearinghouse, other members would be required to meet shortfalls. The Company's liability under these arrangements is not quantifiable and could exceed the cash and securities it has posted to the clearinghouse as collateral. However, the likelihood that the Company would be required to make payments under these agreements is considered remote. Accordingly, no contingent liability is carried on the Condensed Consolidated Balance Sheets for these guarantees. The Company clears its clients' futures and options on futures transactions on an omnibus account basis through unaffiliated FCMs. The Company also contracts with an external provider to facilitate foreign exchange trading for its clients. The Company has agreed to indemnify these unaffiliated FCMs and the external provider for any loss that they may incur from the client transactions introduced to them by the Company. See " Insured Deposit Account Agreement " in Note 14 for a description of the guarantees included in that agreement.

Fair Value Disclosures

Fair Value Disclosures	9 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Fair Value Disclosures Fair Value Measurement — Definition and Hierarchy ASC 820-10, Fair Value Measurement , defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. ASC 820-10 establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability, and are developed based on market data obtained from sources independent of the Company. Unobservable inputs reflect the Company's own assumptions about the assumptions other market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels, as follows: • Level 1 — Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. This category includes active exchange-traded funds, money market mutual funds, mutual funds and equity securities. • Level 2 — Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Such inputs include quoted prices in markets that are not active, quoted prices for similar assets and liabilities in active and inactive markets, inputs other than quoted prices that are observable for the asset or liability and inputs that are derived principally from or corroborated by observable market data by correlation or other means. This category includes most debt securities, U.S. government agency mortgage-backed securities, which consist of Ginnie Mae Home Equity Conversion Mortgages, and other interest-sensitive financial instruments. • Level 3 — Unobservable inputs for the asset or liability, where there is little, if any, observable market activity or data for the asset or liability. The following tables present the Company's fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of June 30, 2019 and September 30, 2018 (dollars in millions): June 30, 2019 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market mutual funds $ 2,533 $ — $ — $ 2,533 Investments segregated and on deposit for regulatory purposes: U.S. government debt securities — 2,847 — 2,847 U.S. government agency mortgage-backed securities — 767 — 767 Subtotal - Investments segregated and on deposit for regulatory purposes — 3,614 — 3,614 Securities owned: U.S. government debt securities — 313 — 313 Other 1 4 — 5 Subtotal - Securities owned 1 317 — 318 Investments available-for-sale: U.S. government debt securities — 1,129 — 1,129 Other assets: Pay-variable interest rate swaps (1) — 45 — 45 U.S. government debt securities — 1 — 1 Subtotal - Other assets — 46 — 46 Total assets at fair value $ 2,534 $ 5,106 $ — $ 7,640 Liabilities: Accounts payable and other liabilities: Securities sold, not yet purchased: Equity securities $ 1 $ — $ — $ 1 (1) See " Fair Value Hedging " in Note 7 for details. September 30, 2018 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market mutual funds $ 2,373 $ — $ — $ 2,373 Investments segregated and on deposit for regulatory purposes: U.S. government debt securities — 225 — 225 U.S. government agency mortgage-backed securities — 1,302 — 1,302 Subtotal - Investments segregated and on deposit for regulatory purposes — 1,527 — 1,527 Securities owned: U.S. government debt securities — 149 — 149 Other 1 6 — 7 Subtotal - Securities owned 1 155 — 156 Investments available-for-sale: U.S. government debt securities — 484 — 484 Other assets: Pay-variable interest rate swaps (1) — 2 — 2 U.S. government debt securities — 1 — 1 Auction rate securities — — 1 1 Subtotal - Other assets — 3 1 4 Total assets at fair value $ 2,374 $ 2,169 $ 1 $ 4,544 Liabilities: Accounts payable and other liabilities: Pay-variable interest rate swaps (1) $ — $ 96 $ — $ 96 (1) See " Fair Value Hedging " in Note 7 for details. There were no transfers between any levels of the fair value hierarchy during the periods covered by this report. Valuation Techniques In general, and where applicable, the Company uses quoted prices in active markets for identical assets or liabilities to determine fair value. This pricing methodology applies to the Company's Level 1 assets and liabilities. If quoted prices in active markets for identical assets and liabilities are not available to determine fair value, then the Company uses quoted prices for similar assets and liabilities or inputs other than the quoted prices that are observable, either directly or indirectly. This pricing methodology applies to the Company's Level 2 assets and liabilities. Level 2 Measurements: Debt securities — Fair values for debt securities are based on prices obtained from an independent pricing vendor. The primary inputs to the valuation include quoted prices for similar assets in active markets, quoted prices for identical or similar assets in markets that are not active, contractual cash flows, benchmark yields and credit spreads. The Company validates the vendor pricing by periodically comparing it to pricing from another independent pricing service. The Company has not adjusted prices obtained from the independent pricing vendor for any periods presented in the condensed consolidated financial statements because no significant pricing differences have been observed. U.S. government agency mortgage-backed securities — Fair values for mortgage-backed securities are based on prices obtained from an independent pricing vendor. The primary inputs to the valuation include quoted prices for similar assets in active markets and in markets that are not active, a market derived prepayment curve, weighted average yields on the underlying collateral and spreads to benchmark indices. The Company validates the vendor pricing by periodically comparing it to pricing from two other independent sources. The Company has not adjusted prices obtained from the independent pricing vendor for any periods presented in the condensed consolidated financial statements because no significant pricing differences have been observed. Interest rate swaps — These derivatives are valued by the Company using a valuation model provided by a third-party service that incorporates interest rate yield curves, which are observable for substantially the full term of the contract. The valuation model is widely accepted in the financial services industry and does not involve significant judgment because most of the inputs are observable in the marketplace. Credit risk is not an input to the valuation because in each case the Company or counterparty has possession of collateral, in the form of cash or U.S. Treasury securities, in amounts equal to or exceeding the fair value of the interest rate swaps. The Company validates the third-party service valuations by comparing them to valuation models provided by the swap counterparties. Level 3 Measurements: The Company has no material assets or liabilities classified as Level 3 of the fair value hierarchy. Fair Value of Financial Instruments Not Recorded at Fair Value Receivable from/payable to brokers, dealers and clearing organizations, receivable from/payable to clients, receivable from/payable to affiliates, other receivables, accounts payable and other liabilities and certain other borrowings are short-term in nature and accordingly are carried at amounts that approximate fair value. These financial instruments are recorded at or near their respective transaction prices and historically have been settled or converted to cash at approximately that value (categorized as Level 2 of the fair value hierarchy). Cash and investments segregated and on deposit for regulatory purposes includes reverse repurchase agreements (securities purchased under agreements to resell). Reverse repurchase agreements are treated as collateralized financing transactions and are carried at amounts at which the securities will subsequently be resold, plus accrued interest. The Company's reverse repurchase agreements generally have a maturity of seven days and are collateralized by securities in amounts exceeding the carrying value of the resale agreements. Accordingly, the carrying value of reverse repurchase agreements approximates fair value (categorized as Level 2 of the fair value hierarchy). Cash and investments segregated and on deposit for regulatory purposes also includes cash held in demand deposit accounts and on deposit with futures commission merchants, for which the carrying values approximate the fair value (categorized as Level 1 of the fair value hierarchy). See Note 3 for a summary of cash and investments segregated and on deposit for regulatory purposes. Securities sold under agreements to repurchase (repurchase agreements) included within other borrowings — Under repurchase agreements the Company receives cash from the counterparties and provides U.S. Treasury securities as collateral. The obligations to repurchase securities sold are reflected as a liability on the Condensed Consolidated Balance Sheets. Repurchase agreements are treated as collateralized financing transactions and are carried at amounts at which the securities will subsequently be repurchased, plus accrued interest. The Company's repurchase agreements are short-term in nature and accordingly the carrying value is a reasonable estimate of fair value (categorized as Level 2 of the fair value hierarchy). Long-term debt — As of June 30, 2019 , the Company's Senior Notes had an aggregate estimated fair value, based on quoted market prices (categorized as Level 1 of the fair value hierarchy), of approximately $3.64 billion , compared to the aggregate carrying value of the Senior Notes on the Condensed Consolidated Balance Sheet of $3.57 billion . As of September 30, 2018 , the Company's Senior Notes had an aggregate estimated fair value, based on quoted market prices, of approximately $2.51 billion , compared to the aggregate carrying value of the Senior Notes on the Condensed Consolidated Balance Sheet of $2.44 billion .

Offsetting Assets and Liabiliti

Offsetting Assets and Liabilities	9 Months Ended
	Jun. 30, 2019
Offsetting [Abstract]
Offsetting Assets and Liabilities	Offsetting Assets and Liabilities Substantially all of the Company's securities sold under agreements to repurchase (repurchase agreements), reverse repurchase agreements, securities borrowing and securities lending activity and derivative financial instruments are transacted under master agreements that may allow for net settlement in the ordinary course of business, as well as offsetting of all contracts with a given counterparty in the event of default by one of the parties. However, for financial statement purposes, the Company does not net balances related to these financial instruments. The following tables present information about the potential effect of rights of setoff associated with the Company's recognized assets and liabilities as of June 30, 2019 and September 30, 2018 (dollars in millions): June 30, 2019 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet Gross Amounts of Recognized Assets and Liabilities Gross Amounts Offset in the Condensed Consolidated Balance Sheet Net Amounts Presented in the Condensed Consolidated Balance Sheet Financial Instruments (5) Collateral Received or Pledged (Including Cash) (6) Net Amount (7) Assets: Investments segregated and on deposit for regulatory purposes: Reverse repurchase agreements $ 500 $ — $ 500 $ — $ (500 ) $ — Receivable from brokers, dealers and clearing organizations: Deposits paid for securities borrowed (1) 1,285 — 1,285 (30 ) (1,234 ) 21 Other assets: Pay-variable interest rate swaps 45 — 45 (45 ) — — Total $ 1,830 $ — $ 1,830 $ (75 ) $ (1,734 ) $ 21 Liabilities: Payable to brokers, dealers and clearing organizations: Deposits received for securities loaned (2)(3) $ 3,124 $ — $ 3,124 $ (30 ) $ (2,822 ) $ 272 September 30, 2018 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet Gross Amounts of Recognized Assets and Liabilities Gross Amounts Offset in the Condensed Consolidated Balance Sheet Net Amounts Presented in the Condensed Consolidated Balance Sheet Financial Instruments (5) Collateral Received or Pledged (Including Cash) (6) Net Amount (7) Assets: Investments segregated and on deposit for regulatory purposes: Reverse repurchase agreements $ 500 $ — $ 500 $ — $ (500 ) $ — Receivable from brokers, dealers Deposits paid for securities borrowed (1) 803 — 803 (41 ) (744 ) 18 Other assets: Pay-variable interest rate swaps 2 — 2 (2 ) — — Total $ 1,305 $ — $ 1,305 $ (43 ) $ (1,244 ) $ 18 Liabilities: Payable to brokers, dealers and clearing organizations: Deposits received for securities loaned (2)(3) $ 2,914 $ — $ 2,914 $ (43 ) $ (2,544 ) $ 327 Securities sold under agreements to repurchase ( 4 ) 96 — 96 (96 ) — — Accounts payable and other liabilities: Pay-variable interest rate swaps 96 — 96 (82 ) — 14 Total $ 3,106 $ — $ 3,106 $ (221 ) $ (2,544 ) $ 341 (1) Included in the gross amounts of deposits paid for securities borrowed is $394 million and $462 million as of June 30, 2019 and September 30, 2018 , respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of cash to the Company. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with securities borrowing transactions and how the Company mitigates those risks. (2) Included in the gross amounts of deposits received for securities loaned is $2.26 billion and $2.01 billion as of June 30, 2019 and September 30, 2018 , respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of securities to the Company. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with securities lending transactions and how the Company mitigates those risks. (3) Substantially all of the Company's securities lending transactions have a continuous contractual term and, upon notice by either party, may be terminated within two business days. The following table summarizes the Company's gross liability for securities lending transactions by the class of securities loaned (dollars in millions): June 30, September 30, Deposits received for securities loaned: Equity securities $ 2,681 $ 2,583 Exchange-traded funds 283 223 Real estate investment trusts 83 19 Closed-end funds 62 74 Other 15 15 Total $ 3,124 $ 2,914 (4) The collateral pledged includes available-for-sale U.S. government debt securities at fair value. All of the Company's repurchase agreements have a remaining contractual maturity of less than 90 days and, upon default by either party, may be terminated at the option of the non-defaulting party. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with repurchase agreements and how the Company mitigates those risks. (5) Amounts represent recognized assets and liabilities that are subject to enforceable master agreements with rights of setoff. (6) Represents the fair value of collateral the Company had received or pledged under enforceable master agreements, limited for table presentation purposes to the net amount of the recognized assets due from or liabilities due to each counterparty. At June 30, 2019 and September 30, 2018 , the Company had received total collateral with a fair value of $1.82 billion and $1.30 billion , respectively, and pledged total collateral with a fair value of $2.85 billion and $2.76 billion , respectively. (7) Represents the amount for which, in the case of net recognized assets, the Company had not received collateral, and in the case of net recognized liabilities, the Company had not pledged collateral.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The following tables present the net change in fair value recorded for each component of other comprehensive income (loss) before and after income tax for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Investments available-for-sale: Unrealized gain (loss) $ 17 $ (4 ) $ 13 $ (2 ) $ — $ (2 ) Net change in investments available-for-sale 17 (4 ) 13 (2 ) — (2 ) Cash flow hedging instruments: Reclassification adjustment for portion of realized loss amortized to net income (1) 1 (1 ) — 1 — 1 Net change in cash flow hedging instruments 1 (1 ) — 1 — 1 Other comprehensive income (loss) $ 18 $ (5 ) $ 13 $ (1 ) $ — $ (1 ) Nine Months Ended June 30, 2019 2018 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Investments available-for-sale: Unrealized gain (loss) $ 42 $ (10 ) $ 32 $ (8 ) $ 1 $ (7 ) Reclassification adjustment for realized loss included in net income (2) — — — 11 (4 ) 7 Net change in investments available-for-sale 42 (10 ) 32 3 (3 ) — Cash flow hedging instruments: Reclassification adjustment for portion of realized loss amortized to net income (1) 3 (1 ) 2 3 — 3 Net change in cash flow hedging instruments 3 (1 ) 2 3 — 3 Other comprehensive income $ 45 $ (11 ) $ 34 $ 6 $ (3 ) $ 3 (1) The before tax reclassification amounts and related tax effects are included in interest on borrowings and provision for income taxes, respectively, on the Condensed Consolidated Statements of Income. (2) The before tax reclassification amount and the related tax effect are included in loss on sale of investments and provision for income taxes, respectively, on the Condensed Consolidated Statements of Income. The following table presents after-tax changes in each component of accumulated other comprehensive income (loss) for the periods indicated (dollars in millions): Three Months Ended June 30, Nine Months Ended June 30, 2019 2018 2019 2018 Investments available-for-sale: Beginning balance $ 12 $ (3 ) $ (7 ) $ (5 ) Other comprehensive income (loss) before reclassifications 13 (2 ) 32 (7 ) Amounts reclassified from accumulated other comprehensive income (loss) — — — 7 Current period change 13 (2 ) 32 — Ending balance $ 25 $ (5 ) $ 25 $ (5 ) Cash flow hedging instruments: Beginning balance $ (18 ) $ (18 ) $ (20 ) $ (20 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1 2 3 Ending balance $ (18 ) $ (17 ) $ (18 ) $ (17 ) Total accumulated other comprehensive income (loss): Beginning balance $ (6 ) $ (21 ) $ (27 ) $ (25 ) Current period change 13 (1 ) 34 3 Ending balance $ 7 $ (22 ) $ 7 $ (22 )

Earnings Per Share

Earnings Per Share	9 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The difference between the numerator and denominator used in the computation of basic and diluted earnings per share consists of common stock equivalent shares related to stock-based compensation for all periods presented. There were no material antidilutive awards for the three and nine months ended June 30, 2019 and 2018 .

Related Party Transactions

Related Party Transactions	9 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Transactions with TD and its Affiliates As a result of the Company's acquisition of TD Waterhouse Group, Inc. during fiscal year 2006, TD became an affiliate of the Company. TD owned approximately 43% of the Company's common stock as of June 30, 2019 . Pursuant to the stockholders agreement between TD and the Company, TD has the right to designate five of the twelve members of the Company's board of directors. The Company transacts business and has extensive relationships with TD and certain of its affiliates. Transactions with TD and its affiliates are discussed and summarized below. Insured Deposit Account Agreement The Company is party to an insured deposit account ("IDA") agreement with TD Bank USA, N.A. ("TD Bank USA"), TD Bank, N.A. and TD. Under the IDA agreement, TD Bank USA and TD Bank, N.A. (together, the "TD Depository Institutions") make available to clients of the Company FDIC-insured (up to specified limits) money market deposit accounts as either designated sweep vehicles or as non-sweep deposit accounts. The Company provides marketing, recordkeeping and support services for the TD Depository Institutions with respect to the money market deposit accounts. In exchange for providing these services, the TD Depository Institutions pay the Company an aggregate marketing fee based on the weighted average yield earned on the client IDA assets, less the actual interest paid to clients, a servicing fee to the TD Depository Institutions and the cost of FDIC insurance premiums. The current IDA agreement became effective as of January 1, 2013 and had an initial term expiring July 1, 2018 . It is automatically renewable for successive five-year terms, provided that it may be terminated by either the Company or the TD Depository Institutions by providing written notice of non-renewal at least two years prior to the initial expiration date or the expiration date of any subsequent renewal period. As of July 1, 2016, notice of non-renewal was not provided by either party; therefore, the IDA agreement was automatically renewed for an additional five-year term on July 1, 2018. The fee earned on the IDA agreement is calculated based on two primary components: (a) the yield on fixed-rate notional investments, based on prevailing fixed rates for identical balances and maturities in the interest rate swap market (generally LIBOR-based) at the time such investments were added to the IDA portfolio (including any adjustments required to adjust the variable rate leg of such swaps to a one-month reset frequency and the overall swap payment frequency to monthly) and (b) the yield on floating-rate investments. As of June 30, 2019 , the IDA portfolio was comprised of approximately 83% fixed-rate notional investments and 17% floating-rate investments. The IDA agreement provides that the Company may designate amounts and maturity dates for the fixed-rate notional investments in the IDA portfolio, subject to certain limitations. For example, if the Company designates that $100 million of deposits be invested in 5 -year fixed-rate investments, and on the day such investment is confirmed by the TD Depository Institutions the prevailing fixed yield for the applicable 5 -year U.S. dollar LIBOR-based swaps is 1.45% , then the Company will earn a gross fixed yield of 1.45% on that portion of the portfolio (before any deductions for interest paid to clients, the servicing fee to the TD Depository Institutions and the cost of FDIC insurance premiums). In the event that (1) the federal funds effective rate is established at 0.75% or greater and (2) the rate on 5 -year U.S. dollar interest rate swaps is equal to or greater than 1.50% for 20 consecutive business days, then the rate earned by the Company on new fixed-rate notional investments will be reduced by 20% of the excess of the 5 -year U.S. dollar swap rate over 1.50% , up to a maximum of 0.10% . The yield on floating-rate investments is calculated daily based on the greater of the following rates published by the Federal Reserve: (1) the interest rate paid by Federal Reserve Banks on balances held in excess of required reserve balances and contractual clearing balances under Regulation D and (2) the daily effective federal funds rate. The interest rates paid to clients are set by the TD Depository Institutions and are not linked to any index. The servicing fee to the TD Depository Institutions under the IDA agreement is equal to 25 basis points on the aggregate average daily balance in the IDA accounts, subject to adjustment as it relates to deposits of less than or equal to $20 billion kept in floating-rate investments or in fixed-rate notional investments with a maturity of up to 24 months ("short-term fixed-rate investments"). For such floating-rate and short-term fixed-rate investments, the servicing fee is equal to the difference of the interest rate earned on the investments less the FDIC premiums paid (in basis points), divided by two. The servicing fee has a floor of 3 basis points (subject to adjustment from time to time to reflect material changes to the TD Depository Institutions' leverage costs) and a maximum of 25 basis points. In the event the marketing fee computation results in a negative amount, the Company must pay the TD Depository Institutions the negative amount. This effectively results in the Company guaranteeing the TD Depository Institutions revenue equal to the servicing fee on the IDA agreement, plus the reimbursement of FDIC insurance premiums. The marketing fee computation under the IDA agreement is affected by many variables, including the type, duration, principal balance and yield of the fixed-rate and floating-rate investments, the prevailing interest rate environment, the amount of client deposits and the yield paid on client deposits. Because a negative marketing fee computation would arise only if there were extraordinary movements in many of these variables, the maximum potential amount of future payments the Company could be required to make under this arrangement cannot be reasonably estimated. Management believes the likelihood that the marketing fee calculation would result in a negative amount is remote. Accordingly, no contingent liability is carried on the Condensed Consolidated Balance Sheets for the IDA agreement. In the event the Company withdraws a notional investment prior to its maturity, the Company is required to reimburse the TD Depository Institutions an amount equal to the economic replacement value of the investment, as defined in the IDA agreement. See "General Contingencies" in Note 9 for a discussion of how the Company mitigates the risk of losses due to the early withdrawal of fixed-rate notional investments. In addition, the Company has various other services agreements and transactions with TD and its affiliates. The following tables summarize revenues and expenses resulting from transactions with TD and its affiliates for the periods indicated (dollars in millions): Revenues from TD and its Affiliates Condensed Consolidated Statement of Income Classification Three Months Ended June 30, Nine Months Ended June 30, Description 2019 2018 2019 2018 Insured Deposit Account Agreement Bank deposit account fees $ 392 $ 363 $ 1,193 $ 1,056 Order Routing Agreement (1) Other revenues 6 1 17 3 Other Various 2 7 19 21 Total revenues $ 400 $ 371 $ 1,229 $ 1,080 Expenses to TD and its Affiliates Condensed Consolidated Statement of Income Classification Three Months Ended June 30, Nine Months Ended June 30, Description 2019 2018 2019 2018 Order Routing Agreement (1) Other expense $ 4 N/A $ 13 N/A Other Various 3 2 6 6 Total expenses $ 7 $ 2 $ 19 $ 6 (1) Prior to fiscal year 2019, the Company accounted for revenues associated with the Order Routing Agreement between the Company and an affiliate of TD on a net basis through other revenues. Following the adoption of the new revenue recognition standard (ASU 2014-09) on October 1, 2018, the Company began accounting for Order Routing Agreement revenues on a gross basis. The Company adopted the new guidance using the modified retrospective approach, which requires the standard be applied only to the most current period presented; therefore, the prior period has not been adjusted to reflect the current period presentation. See "Recently Adopted Accounting Pronouncements" in Note 1 for additional details regarding the amended guidance. The following table summarizes the classification and amount of receivables from and payables to TD and its affiliates on the Condensed Consolidated Balance Sheets resulting from related party transactions (dollars in millions): June 30, September 30, Assets: Receivable from affiliates $ 127 $ 151 Liabilities: Payable to brokers, dealers and clearing organizations $ 23 $ 47 Payable to affiliates 3 7 Accounts payable and other liabilities 2 — Payables to brokers, dealers and clearing organizations primarily relate to securities lending activity and are settled in accordance with customary contractual terms. Receivables from and payables to TD affiliates resulting from client cash sweep activity are generally settled in cash the next business day. Other receivables from and payables to affiliates of TD are generally settled in cash on a monthly basis. As of September 30, 2018, payable to affiliates on the Condensed Consolidated Balance Sheet included $38 million of liabilities assumed in connection with the acquisition of Scottrade. These liabilities were settled during the first quarter of fiscal year 2019. TD, along with other financial institutions, is participating as a lender under the Parent Revolving Facility and the TDAC Revolving Facilities. For additional information regarding the Company's revolving facilities, see Note 7, Long-term Debt and Other Borrowings. As of June 30, 2019 and September 30, 2018, the total lending commitment received from TD under these credit facilities was $221 million and $257 million , respectively. During the nine months ended June 30, 2019 , the Company paid approximately $1 million

Accelerated Stock Repurchase Ag

Accelerated Stock Repurchase Agreements	9 Months Ended
	Jun. 30, 2019
Accelerated Stock Repurchase [Abstract]
Accelerated Stock Repurchase Agreements	Accelerated Stock Repurchase Agreements On March 26, 2019, the Company entered into an agreement with an investment bank counterparty to purchase shares of its common stock under an accelerated stock repurchase transaction (the "March 2019 ASR Agreement"). The Company paid $350 million to the counterparty and received an initial delivery of 5.6 million shares of its common stock on March 28, 2019, representing 80% of the potential shares to be repurchased based on the closing stock price of $49.64 on March 26, 2019. Settlement of the transaction is scheduled to occur after the end of an averaging period and is subject to early termination by the counterparty. The averaging period began on March 27, 2019 and will end no earlier than July 29, 2019 or later than September 25, 2019. The total number of shares to be repurchased by the Company from the counterparty will be based on the average of the daily volume-weighted average share prices of the Company's common stock during the averaging period, less a pre-determined discount, up to a maximum of 14.1 million shares. If the total number of shares to be repurchased exceeds the number of shares delivered on March 28, 2019, the Company will receive the remaining balance of shares from the investment bank counterparty. If the total number of shares to be repurchased is less than the number of shares delivered on March 28, 2019, the Company has the contractual right to deliver to the investment bank counterparty either shares of its common stock or cash. The Company expects to receive additional shares upon final settlement of the March 2019 ASR Agreement. On November 27, 2018, the Company entered into an agreement with an investment bank counterparty to purchase $60 million of its common stock under an accelerated stock repurchase transaction (the "November 2018 ASR Agreement"). Pursuant to the terms of the November 2018 ASR Agreement, the Company received an initial delivery of 0.9 million shares of its common stock on November 30, 2018 and received an additional 0.3 million shares upon settlement of the transaction on March 5, 2019. The Company ultimately repurchased a total of approximately 1.2 million shares under the November 2018 ASR Agreement at a net weighted average price of $52.12 per share. On September 12, 2018, the Company entered into an agreement with an investment bank counterparty to purchase $150 million of its common stock under an accelerated stock repurchase transaction (the "September 2018 ASR Agreement"). Pursuant to the terms of the September 2018 ASR Agreement, the Company received an initial delivery of 2.2 million shares of its common stock on September 13, 2018 and received an additional 0.6 million shares upon settlement of the transaction on October 16, 2018. The Company ultimately repurchased a total of approximately 2.8 million shares under the September 2018 ASR Agreement at a net weighted average price of $53.13 per share. The Company treated the ASR agreements as forward contracts indexed to its own common stock. The forward contracts met all of the applicable criteria for equity classification, including the Company's right to settle in shares. The Company reflected the shares received from the investment bank counterparties as treasury stock as of the dates the shares were delivered, which resulted in reductions of the outstanding shares used to calculate the weighted average common shares outstanding for both basic and diluted earnings per share during the respective periods.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition On October 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers (ASC Topic 606) , and related ASUs using a modified retrospective approach for all contracts that were not completed as of October 1, 2018. The cumulative effect of the changes made to the Company's Condensed Consolidated Balance Sheet as of October 1, 2018 for the adoption of ASU 2014-09 were as follows (dollars in millions): Balance at September 30, 2018 Adjustments from Adoption of ASU 2014-09 Balance at October 1, 2018 Assets: Other assets $ 212 $ 37 $ 249 Liabilities: Deferred income taxes 177 9 186 Stockholders' equity: Retained earnings 7,011 28 7,039 The modified retrospective transition method does not require the Company to recast the prior year financial statements; although, ASU 2014-09 requires the Company to provide additional disclosures for the amount by which each financial statement line item is affected by the adoption of the standard. The financial statement line items affected by the adoption of ASU 2014-09 are as follows (dollars in millions): As of June 30, 2019 Condensed Consolidated Balance Sheet As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Assets: Other assets $ 285 $ 255 $ 30 Liabilities: Deferred income taxes 219 212 7 Stockholders' equity: Retained earnings 8,194 8,171 23 Three Months Ended June 30, 2019 Condensed Consolidated Statement of Income As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Revenues: Other revenues $ 59 $ 40 $ 19 Operating expenses: Employee compensation and benefits 325 323 2 Clearing and execution costs 59 47 12 Other 61 54 7 Provision for income taxes 188 188 — Net income 555 557 (2 ) Earnings per share — diluted $ 1.00 $ 1.01 $ (0.01 ) Nine Months Ended June 30, 2019 Condensed Consolidated Statement of Income As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Revenues: Other revenues $ 126 $ 82 $ 44 Operating expenses: Employee compensation and benefits 982 975 7 Clearing and execution costs 161 140 21 Other 142 119 23 Provision for income taxes 530 532 (2 ) Net income 1,658 1,663 (5 ) Earnings per share — diluted $ 2.96 $ 2.97 $ (0.01 ) The following tables set forth the disaggregation of the Company's revenue by major source for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 % Change Revenues: Transaction-based revenues: Commissions $ 320 $ 334 (4 )% Order routing revenue 117 119 (2 )% Other 40 37 8 % Total transaction-based revenues 477 490 Asset-based revenues: Bank deposit account fees 421 387 9 % Net interest revenue 383 332 15 % Investment product fees 151 140 8 % Total asset-based revenues 955 859 Other revenues 59 33 79 % Net revenues $ 1,491 $ 1,382 Nine Months Ended June 30, 2019 2018 % Change Revenues: Transaction-based revenues: Commissions $ 1,010 $ 1,042 (3 )% Order routing revenue 365 342 7 % Other 125 103 21 % Total transaction-based revenues 1,500 1,487 Asset-based revenues: Bank deposit account fees 1,280 1,149 11 % Net interest revenue 1,120 916 22 % Investment product fees 431 414 4 % Total asset-based revenues 2,831 2,479 Other revenues 126 88 43 % Net revenues $ 4,457 $ 4,054 The amount of revenue recognized by the Company is measured based on the consideration specified in contracts with its clients. The Company recognizes revenue when a performance obligation is satisfied over time as the services are performed or at a point in time depending on the nature of the services provided as further discussed below. Transaction-Based Revenues Transaction-based revenues primarily consists of trading commissions earned on trade execution, net of promotional allowances, and order routing revenue. The primary factors driving the Company's transaction-based revenues are total trades and average commissions per trade. Commission rates are based on rates established by the Company, which vary by type of trade. Transaction-based revenues are earned and recognized at a point in time, on a trade-date basis, as clients execute trades. These trades are generally settled and trading commissions are collected from the Company's clients within one to two business days after the trade date. Order routing revenues are generated from arrangements with market destinations to receive cash payments in exchange for routing trade orders to these firms for execution and are generally collected from the market destinations on a monthly basis. Securities owned by clients, including those that collateralize margin or similar transactions, are not reflected in the accompanying condensed consolidated financial statements. Asset-Based Revenues Asset-based revenues consists of bank deposit account fees, net interest revenue and investment product fees. The primary factors driving the Company's asset-based revenues are average balances and average rates. Average balances consist primarily of average client bank deposit account balances, average client margin balances, average segregated cash balances, average client credit balances, average fee-based investment balances and average securities borrowing and lending balances. Average rates consist of the average interest rates and fees earned and paid on such balances. Bank deposit account fees Bank deposit account fees consists of revenues earned and recognized over time resulting from a sweep program that is offered to eligible clients of the Company whereby clients' uninvested cash is swept off-balance sheet to FDIC-insured (up to specified limits) accounts with Sweep Program Counterparties participating in the program. These revenues are based on the return of floating-rate and fixed-rate notional investments, less the actual interest paid to clients and other applicable fees. Bank deposit account fees are collected from the Sweep Program Counterparties on a monthly basis. See " Insured Deposit Account Agreement " in Note 14 for a description of the sweep arrangement between the Company and TD. Net interest revenue Net interest revenue, which is generated from financial instruments covered by various other areas of GAAP, is not within the scope of ASC 606 and is included in the table above to reconcile to net revenues disclosed within the Condensed Consolidated Statements of Income. Net interest revenue primarily consists of income generated by interest charged to clients on margin balances, net interest revenue from securities borrowed and securities loaned transactions and interest earned on client cash, net of interest paid to clients on their credit balances. Investment product fees Investment product fee revenue consists of revenues earned and recorded over time on client assets invested in money market mutual funds, other mutual funds and certain investment programs. Investment product fees also includes fees earned on client assets managed by independent registered investment advisors ("RIAs") utilizing the Company's trading and investing platforms. Investment product fees are collected from clients and RIAs on a monthly or quarterly basis. Primary revenue sources within investment product fees are described below. The following tables present the significant components of investment product fees for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 % Change Investment product fees: Mutual fund service fees $ 73 $ 63 16 % Investment program fees 70 70 0 % Other 8 7 14 % Total investment product fees $ 151 $ 140 Nine Months Ended June 30, 2019 2018 % Change Investment product fees: Mutual funds service fees $ 208 $ 186 12 % Investment program fees 199 202 (1 )% Other 24 26 (8 )% Total investment product fees $ 431 $ 414 Mutual fund service fees includes shareholder services fees and SEC Rule 12b-1 service and distribution fees. Shareholder services fees are earned on the Company's client assets invested in money market mutual funds and other mutual funds for record-keeping and administrative services provided to these funds. The Company earns SEC Rule 12b-1 service and distribution fees for marketing and distribution services provided to these funds. The fees earned are based on contractual rates applied to the average daily net asset value of eligible shares of a respective fund held by the Company's clients. Shareholder services fees are earned over time and collected from the funds on a monthly or quarterly basis. SEC Rule 12b-1fees are also earned over time and collected from the funds on a monthly or quarterly basis, as the variable consideration of a transaction price is no longer constrained and the value of consideration can be determined as discussed previously. Investment program fees are earned through fees charged to clients enrolled in product offerings which are actively managed by TD Ameritrade Investment Management, LLC, a wholly-owned subsidiary of the Company. These fees are earned over time and are based on contractual rates applied to asset balances held by the Company's clients in these product offerings. Certain program fees are based on quarter-end balances and are collected from clients in advance, at the beginning of each calendar quarter. Revenues collected on a quarterly basis, less refunds for clients ceasing participation in the program, are recognized during the quarter as performance obligations are satisfied. Other program fees are based on average daily asset balances and collected from clients on a monthly basis. The Company also earns investment program fees through referral and asset-based program fees on its client assets managed by independent RIAs utilizing the Company's platform. These fees are earned based on contractual rates applied to the client's average daily asset balances under management. Referral fees are earned over time and collected from the independent RIAs on a monthly or quarterly basis, as the variable consideration of a transaction price is no longer constrained and the value of consideration can be determined as discussed previously. Asset-based program fees are also earned over time and collected from the independent RIAs on a monthly or quarterly basis. Other Revenues Other revenues primarily include proxy income, solicit and tender fees and other fees charged for ancillary services provided by the Company to its clients. In addition, other revenues include fair market value adjustments and gains/losses associated with investments held by the Company's broker-dealer subsidiaries. Other revenues generated from investments is covered by various other areas of GAAP, is not within the scope of ASC 606 and is included in the table above to reconcile to net revenues disclosed within the Condensed Consolidated Statements of Income. Proxy fee income is earned and collected at a point in time when the Company distributes proxy statements to its clients on behalf of a registrant and the revenue is based on the volume of proxies distributed and the rate per unit charged to each registrant. Solicit and tender fees are earned and collected from clients at a point in time when the Company has satisfied its obligation to maintain its client accounts holding securities affected by corporate actions. Contract Balances The following table presents the opening and closing balances of the Company's receivables from contracts with clients that are within the scope of ASC 606 on the Condensed Consolidated Balance Sheets (dollars in millions): Contract Balances Receivable from Clients Receivable from Affiliates Other Receivables Total Receivables from Contracts with Clients Opening balance, October 1, 2018 $ 16 $ 7 $ 115 $ 138 Closing balance, June 30, 2019 17 7 127 151 Increase $ 1 $ — $ 12 $ 13 The difference between the opening and closing balances of the Company's receivables from contracts with clients primarily results from the timing difference between the Company's performance and the client's payment. No other significant contract assets or liabilities exist as of June 30, 2019 and October 1, 2018. Unsatisfied Performance Obligations

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe condensed consolidated financial statements include the accounts of TD Ameritrade Holding Corporation (the "Parent") and its wholly-owned subsidiaries (collectively, the "Company"). Intercompany balances and transactions have been eliminated.
Recently Adopted & Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements ASU 2016-18 — On October 1, 2018, the Company adopted Accounting Standards Update ("ASU") 2016-18, Restricted Cash , using a retrospective transition method to each period presented. This ASU amends the guidance in Accounting Standards Codification ("ASC") Topic 230, Statement of Cash Flows , and is intended to reduce the diversity in the classification and presentation of changes in restricted cash on the statement of cash flows. The amendments within this ASU require that the reconciliation of the beginning-of-period and end-of-period cash and cash equivalents amounts shown on the statement of cash flows include restricted cash and restricted cash equivalents. If restricted cash and restricted cash equivalents are presented separately from cash and cash equivalents on the balance sheet, an entity is required to reconcile the amounts presented on the statement of cash flows to the amounts on the balance sheet. An entity is also required to disclose information regarding the nature of the restrictions. Under the retrospective transition method, the Company recorded a decrease of $5.1 billion in cash flows from operating activities for the nine months ended June 30, 2018 to reflect the reclassification of changes in restricted cash and restricted cash equivalents amounts from the operating section to the beginning-of-period and end-of-period cash, cash equivalents, restricted cash and restricted cash equivalents amounts within the Condensed Consolidated Statements of Cash Flows. See Note 2 for additional information regarding restricted cash and restricted cash equivalents. ASU 2016-16 — On October 1, 2018, the Company adopted ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. This ASU amends the guidance in ASC Topic 740, Income Taxes . The amendments in this ASU are intended to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory by requiring an entity to recognize the income tax consequences when a transfer occurs, instead of when the asset is sold to a third party. The adoption of ASU 2016-16 did not have an impact on the Company's condensed consolidated financial statements. ASU 2014-09 — On October 1, 2018, the Company adopted ASU 2014-09, Revenue from Contracts with Customers , using a modified retrospective approach, which requires the standard be applied only to the most current period presented, with the cumulative effect of initially applying the standard recognized at the date of initial application. The new revenue recognition standard is intended to clarify the principles of recognizing revenue from contracts with customers and to improve financial reporting by creating common revenue recognition guidance for U.S. GAAP and International Financial Reporting Standards. This ASU supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition, and most industry-specific guidance. Entities are required to apply the following steps when recognizing revenue under ASU 2014-09: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This ASU also requires additional disclosures related to the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. The adoption of this standard did not have a material impact on the Company's financial condition, results of operations or cash flows, as the satisfaction of performance obligations under the new guidance is materially consistent with the Company's previous revenue recognition policies. However, the adoption of this standard did impact the Company by: (1) requiring the capitalization of sales commissions paid to employees for obtaining new contracts with clients and (2) accounting for revenues from certain contracts on a gross basis when the Company is acting as a principal, as compared to the prior guidance, which allowed for these contracts to be accounted for on a net basis. For additional information on the Company's adoption of the amended guidance, see Note 16 , Revenue Recognition. The new guidance does not apply to revenue associated with financial instruments, such as interest revenue, which is accounted for under other GAAP. Accordingly, net interest revenue was not impacted. Recently Issued Accounting Pronouncements ASU 2017-12 — In August 2017, the Financial Accounting Standards Board ("FASB") issued ASU 2017-12, Targeted Improvements to Accounting for Hedging Activities , which will amend the guidance in ASC Topic 815, Derivatives and Hedging. The objective of this ASU is to improve the financial reporting of hedging relationships to better portray the economic results of an entity's risk management activities in its financial statements through changes to both the designation and measurement guidance for qualifying hedging relationships and to the presentation of hedge results. In addition, the amendments in this ASU make certain targeted improvements that are intended to simplify the application of the hedge accounting guidance in current GAAP. All transition requirements and elections under ASU 2017-12 should be applied to hedging relationships existing on the date of adoption, with the effect of the adoption reflected as of the beginning of the fiscal year of adoption. The amended presentation and disclosure guidance is required only prospectively. Subsequent to issuing ASU 2017-12, the FASB has issued additional standards for the purpose of providing codification improvements as well as introducing an additional benchmark interest rate (SOFR) for hedge accounting purposes. SOFR is a volume-weighted median interest rate that is calculated daily based on overnight transactions from the prior day's trading activity in specified segments of the U.S. Treasury repo market. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2017-12. ASU 2017-12 will be effective for the Company's fiscal year beginning October 1, 2019, with early adoption permitted. The Company does not expect this ASU to have a material impact on its condensed consolidated financial statements. ASU 2016-13 — In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments . The main objective of ASU 2016-13 is to provide financial statement users with more decision-useful information about an entity's expected credit losses on financial instruments and other commitments to extend credit at each reporting date. To achieve this objective, the amendments in this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to develop credit loss estimates. Subsequent to issuing ASU 2016-13, the FASB has issued additional standards for the purpose of clarifying certain aspects of ASU 2016-13, as well as providing codification improvements and targeted transition relief under the standard. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2016-13. ASU 2016-13 will be effective for the Company's fiscal year beginning October 1, 2020, using a modified retrospective approach. Early adoption is permitted. The Company is currently assessing the impact this ASU will have on its condensed consolidated financial statements. ASU 2016-02 — In February 2016, the FASB issued ASU 2016-02, Leases . This ASU will supersede the guidance in ASC Topic 840, Leases . Under ASU 2016-02, for lease arrangements exceeding a 12-month term, a lessee will be required to recognize in the balance sheet a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. ASU 2016-02 will retain a distinction between finance and operating leases; however, the principal difference between the previous guidance and the new guidance is that lease assets and liabilities arising from operating leases will be recognized in the balance sheet under the new guidance. The recognition, measurement and presentation of expenses and cash flows arising from a lease by a lessee will not significantly change from current GAAP. The accounting applied by a lessor will be largely unchanged from that applied under current GAAP. Subsequent to issuing ASU 2016-02, the FASB has issued additional standards for the purpose of clarifying certain aspects of ASU 2016-02 and providing an additional (optional) transition method with which to adopt the new leases standard. The subsequently issued ASUs have the same effective date and transition requirements as ASU 2016-02. Under ASU 2016-02, an entity may apply the amendments by using one of the following two methods: (1) recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach or (2) apply the standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company plans to adopt the new lease accounting guidance on October 1, 2019 by applying the standard at the adoption date and recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Company does not expect this guidance to have a material impact on its earnings per share (EPS); however, upon the adoption of the lease standard, the Company will recognize a right-of-use asset and a lease liability on the Condensed Consolidated Balance Sheet, primarily related to leases of its retail branch offices and administrative and operational facilities. Based upon the Company's current lease portfolio, the initial recognition and measurement of the right-of-use asset and lease liability are each expected to be approximately 1% of the Company's total assets and will be primarily based on the present value of the Company's remaining operating lease payments. The Company is in the process of refining its methodology to estimate the right-of-use asset and lease liability, testing software updates and finalizing the internal control structure that will support these accounting changes.
Loss Contingencies (ASC) 450	ASC 450, Loss Contingencies,
Fair Value Measurement (ASC) 820-10	ASC 820-10, Fair Value Measurement , defines fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. ASC 820-10 establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs reflect the assumptions market participants would use in pricing the asset or liability, and are developed based on market data obtained from sources independent of the Company. Unobservable inputs reflect the Company's own assumptions about the assumptions other market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances.
Revenue Recognition (ASC) 606	Mutual fund service fees includes shareholder services fees and SEC Rule 12b-1 service and distribution fees. Shareholder services fees are earned on the Company's client assets invested in money market mutual funds and other mutual funds for record-keeping and administrative services provided to these funds. The Company earns SEC Rule 12b-1 service and distribution fees for marketing and distribution services provided to these funds. The fees earned are based on contractual rates applied to the average daily net asset value of eligible shares of a respective fund held by the Company's clients. Shareholder services fees are earned over time and collected from the funds on a monthly or quarterly basis. SEC Rule 12b-1fees are also earned over time and collected from the funds on a monthly or quarterly basis, as the variable consideration of a transaction price is no longer constrained and the value of consideration can be determined as discussed previously. Investment program fees are earned through fees charged to clients enrolled in product offerings which are actively managed by TD Ameritrade Investment Management, LLC, a wholly-owned subsidiary of the Company. These fees are earned over time and are based on contractual rates applied to asset balances held by the Company's clients in these product offerings. Certain program fees are based on quarter-end balances and are collected from clients in advance, at the beginning of each calendar quarter. Revenues collected on a quarterly basis, less refunds for clients ceasing participation in the program, are recognized during the quarter as performance obligations are satisfied. Other program fees are based on average daily asset balances and collected from clients on a monthly basis. The Company also earns investment program fees through referral and asset-based program fees on its client assets managed by independent RIAs utilizing the Company's platform. These fees are earned based on contractual rates applied to the client's average daily asset balances under management. Referral fees are earned over time and collected from the independent RIAs on a monthly or quarterly basis, as the variable consideration of a transaction price is no longer constrained and the value of consideration can be determined as discussed previously. Asset-based program fees are also earned over time and collected from the independent RIAs on a monthly or quarterly basis. Other Revenues Other revenues primarily include proxy income, solicit and tender fees and other fees charged for ancillary services provided by the Company to its clients. In addition, other revenues include fair market value adjustments and gains/losses associated with investments held by the Company's broker-dealer subsidiaries. Other revenues generated from investments is covered by various other areas of GAAP, is not within the scope of ASC 606 and is included in the table above to reconcile to net revenues disclosed within the Condensed Consolidated Statements of Income. Proxy fee income is earned and collected at a point in time when the Company distributes proxy statements to its clients on behalf of a registrant and the revenue is based on the volume of proxies distributed and the rate per unit charged to each registrant. Solicit and tender fees are earned and collected from clients at a point in time when the Company has satisfied its obligation to maintain its client accounts holding securities affected by corporate actions. The amount of revenue recognized by the Company is measured based on the consideration specified in contracts with its clients. The Company recognizes revenue when a performance obligation is satisfied over time as the services are performed or at a point in time depending on the nature of the services provided as further discussed below. Transaction-Based Revenues Transaction-based revenues primarily consists of trading commissions earned on trade execution, net of promotional allowances, and order routing revenue. The primary factors driving the Company's transaction-based revenues are total trades and average commissions per trade. Commission rates are based on rates established by the Company, which vary by type of trade. Transaction-based revenues are earned and recognized at a point in time, on a trade-date basis, as clients execute trades. These trades are generally settled and trading commissions are collected from the Company's clients within one to two business days after the trade date. Order routing revenues are generated from arrangements with market destinations to receive cash payments in exchange for routing trade orders to these firms for execution and are generally collected from the market destinations on a monthly basis. Securities owned by clients, including those that collateralize margin or similar transactions, are not reflected in the accompanying condensed consolidated financial statements. Asset-Based Revenues Asset-based revenues consists of bank deposit account fees, net interest revenue and investment product fees. The primary factors driving the Company's asset-based revenues are average balances and average rates. Average balances consist primarily of average client bank deposit account balances, average client margin balances, average segregated cash balances, average client credit balances, average fee-based investment balances and average securities borrowing and lending balances. Average rates consist of the average interest rates and fees earned and paid on such balances. Bank deposit account fees Bank deposit account fees consists of revenues earned and recognized over time resulting from a sweep program that is offered to eligible clients of the Company whereby clients' uninvested cash is swept off-balance sheet to FDIC-insured (up to specified limits) accounts with Sweep Program Counterparties participating in the program. These revenues are based on the return of floating-rate and fixed-rate notional investments, less the actual interest paid to clients and other applicable fees. Bank deposit account fees are collected from the Sweep Program Counterparties on a monthly basis. See " Insured Deposit Account Agreement " in Note 14 for a description of the sweep arrangement between the Company and TD. Net interest revenue Net interest revenue, which is generated from financial instruments covered by various other areas of GAAP, is not within the scope of ASC 606 and is included in the table above to reconcile to net revenues disclosed within the Condensed Consolidated Statements of Income. Net interest revenue primarily consists of income generated by interest charged to clients on margin balances, net interest revenue from securities borrowed and securities loaned transactions and interest earned on client cash, net of interest paid to clients on their credit balances. Investment product fees Investment product fee revenue consists of revenues earned and recorded over time on client assets invested in money market mutual funds, other mutual funds and certain investment programs. Investment product fees also includes fees earned on client assets managed by independent registered investment advisors ("RIAs") utilizing the Company's trading and investing platforms. Investment product fees are collected from clients and RIAs on a monthly or quarterly basis. Primary revenue sources within investment product fees are described below.

Cash, Cash Equivalents, Restr_2

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Tables)	9 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Summary of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents reported within the Condensed Consolidated Balance Sheets to the total of the same amounts shown in the Condensed Consolidated Statements of Cash Flows (dollars in millions): June 30, September 30, Cash and cash equivalents $ 2,953 $ 2,690 Restricted cash and restricted cash equivalents included in cash and investments segregated and on deposit for regulatory purposes 6,332 1,858 Total cash, cash equivalents, restricted cash and restricted cash equivalents shown in the Condensed Consolidated Statements of Cash Flows $ 9,285 $ 4,548 The Company's cash and cash equivalents is summarized in the following table (dollars in millions): June 30, September 30, Broker-dealer subsidiaries $ 1,715 $ 2,094 Corporate 931 342 Trust company subsidiary 202 124 Futures commission merchant and forex dealer member subsidiary 87 89 Investment advisory subsidiaries 18 41 Total cash and cash equivalents $ 2,953 $ 2,690
Reconciliation of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents reported within the Condensed Consolidated Balance Sheets to the total of the same amounts shown in the Condensed Consolidated Statements of Cash Flows (dollars in millions): June 30, September 30, Cash and cash equivalents $ 2,953 $ 2,690 Restricted cash and restricted cash equivalents included in cash and investments segregated and on deposit for regulatory purposes 6,332 1,858 Total cash, cash equivalents, restricted cash and restricted cash equivalents shown in the Condensed Consolidated Statements of Cash Flows $ 9,285 $ 4,548 Cash and investments segregated and on deposit for regulatory purposes consists of the following (dollars in millions): June 30, September 30, Cash in demand deposit accounts $ 2,861 $ 956 U.S. government debt securities 2,822 200 U.S. government agency mortgage-backed securities 767 1,302 Reverse repurchase agreements (collateralized by U.S. government debt securities) 500 500 Cash on deposit with futures commission merchants 149 202 U.S. government debt securities on deposit with futures commission merchant 25 25 Total $ 7,124 $ 3,185

Cash and Investments Segregat_2

Cash and Investments Segregated and on Deposit for Regulatory Purposes (Tables)	9 Months Ended
	Jun. 30, 2019
Restricted Cash and Investments [Abstract]
Cash and Investments Segregated and on Deposit for Regulatory Purposes	The following table provides a reconciliation of cash, cash equivalents, restricted cash and restricted cash equivalents reported within the Condensed Consolidated Balance Sheets to the total of the same amounts shown in the Condensed Consolidated Statements of Cash Flows (dollars in millions): June 30, September 30, Cash and cash equivalents $ 2,953 $ 2,690 Restricted cash and restricted cash equivalents included in cash and investments segregated and on deposit for regulatory purposes 6,332 1,858 Total cash, cash equivalents, restricted cash and restricted cash equivalents shown in the Condensed Consolidated Statements of Cash Flows $ 9,285 $ 4,548 Cash and investments segregated and on deposit for regulatory purposes consists of the following (dollars in millions): June 30, September 30, Cash in demand deposit accounts $ 2,861 $ 956 U.S. government debt securities 2,822 200 U.S. government agency mortgage-backed securities 767 1,302 Reverse repurchase agreements (collateralized by U.S. government debt securities) 500 500 Cash on deposit with futures commission merchants 149 202 U.S. government debt securities on deposit with futures commission merchant 25 25 Total $ 7,124 $ 3,185

Investments Available-for-Sal_2

Investments Available-for-Sale (Tables)	9 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost and Fair Value of Available-for-Sale Securities	The following tables present the amortized cost and fair value of available-for-sale securities (dollars in millions): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: U.S. Treasury securities $ 1,096 $ 33 $ — $ 1,129 September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: U.S. Treasury securities $ 493 $ — $ (9 ) $ 484
Schedule of Contractual Maturities of Available-for-Sale Securities	The following table presents the contractual maturities of available-for-sale securities as of June 30, 2019 (dollars in millions): Amortized Cost Fair Value Available-for-sale U.S. Treasury securities: Due within one to five years $ 384 $ 407 Due within five to ten years 712 722 Total available-for-sale U.S. Treasury securities $ 1,096 $ 1,129

Exit Liabilities (Tables)

Exit Liabilities (Tables)	9 Months Ended
	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Summary of the Activity in Exit Liabilities During the Period	The following tables summarize activity in the Company's exit liabilities for the three and nine month periods ended June 30, 2019 and 2018 , which are included in accounts payable and other liabilities on the Condensed Consolidated Balance Sheets (dollars in millions): Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, March 31, 2019 $ 5 $ 3 $ 8 Costs incurred and charged to expense 2 (1) — 2 Costs paid or otherwise settled (2 ) — (2 ) Balance, June 30, 2019 $ 5 $ 3 $ 8 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, March 31, 2018 $ 113 $ 38 $ 151 Costs incurred and charged to expense 31 (1) 17 (2) 48 Costs paid or otherwise settled (106 ) (24 ) (130 ) Balance, June 30, 2018 $ 38 $ 31 $ 69 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, September 30, 2018 $ 21 $ 48 $ 69 Costs incurred and charged to expense 6 (1) (2 ) (2) 4 Costs paid or otherwise settled (22 ) (43 ) (65 ) Balance, June 30, 2019 $ 5 $ 3 $ 8 Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Balance, September 30, 2017 $ 138 $ — $ 138 Exit liabilities assumed - post closing adjustments — 9 9 Costs incurred and charged to expense 209 (1) 178 (2) 387 Costs paid or otherwise settled (309 ) (156 ) (465 ) Balance, June 30, 2018 $ 38 $ 31 $ 69 (1) Costs incurred for severance pay and other employment benefits are included in employee compensation and benefits on the Condensed Consolidated Statements of Income. (2) Costs incurred for contract termination and other costs are primarily included in other operating expense and professional services on the Condensed Consolidated Statements of Income.
Summary of the Cumulative Amount of Acquisition-Related Exit Costs	The following table summarizes the cumulative amount of acquisition-related exit costs incurred by the Company related to the Scottrade acquisition as of June 30, 2019 (dollars in millions): Severance Pay and Other Employment Benefits Contract Termination and Other Costs Total Exit liabilities assumed in business acquisition $ 100 $ 9 $ 109 Employee compensation and benefits 267 — 267 Clearing and execution costs — 1 1 Communications — 1 1 Occupancy and equipment costs — 7 7 Professional services — 30 30 Other operating expense — 171 171 Other non-operating expense — 2 2 Total $ 367 $ 221 $ 588

Long-term Debt and Other Borr_2

Long-term Debt and Other Borrowings (Tables)	9 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt and Other Borrowings	Long-term debt and other borrowings consist of the following (dollars in millions): June 30, 2019 Face Value Unamortized Discounts and Debt Issuance Costs Fair Value Adjustment (1) Net Carrying Value Long-term debt: Senior Notes: 5.600% Notes due 2019 $ 500 $ — $ 2 $ 502 Variable-rate Notes due 2021 600 (3 ) — 597 2.950% Notes due 2022 750 (3 ) 4 751 3.75% Notes due 2024 400 (4 ) — 396 3.625% Notes due 2025 500 (3 ) 19 516 3.300% Notes due 2027 800 (8 ) 20 812 Total long-term debt $ 3,550 $ (21 ) $ 45 $ 3,574 September 30, 2018 Face Value Unamortized Discounts and Debt Issuance Costs Fair Value Adjustment (1) Net Carrying Value Other borrowings: Securities sold under agreements to repurchase $ 96 $ — $ — $ 96 Long-term debt: Senior Notes: 5.600% Notes due 2019 500 (1 ) 2 501 2.950% Notes due 2022 750 (4 ) (27 ) 719 3.625% Notes due 2025 500 (3 ) (17 ) 480 3.300% Notes due 2027 800 (9 ) (52 ) 739 Subtotal - Long-term debt 2,550 (17 ) (94 ) 2,439 Total long-term debt and other borrowings $ 2,646 $ (17 ) $ (94 ) $ 2,535 (1) Fair value adjustments relate to changes in the fair value of the debt while in a fair value hedging relationship. See " Fair Value Hedging " below.
Schedule of Maturities of Long-term Debt	Fiscal year maturities on long-term debt outstanding at June 30, 2019 are as follows (dollars in millions): 2019 Remaining $ — 2020 500 2021 — 2022 1,350 2023 — Thereafter 1,700 Total $ 3,550
Schedule of Gains and Losses Resulting from Changes in Fair Value of Interest Rate Swaps and Hedged Fixed Rate Debt	The following table summarizes gains and losses resulting from changes in the fair value of interest rate swaps designated as fair value hedges and the hedged fixed-rate debt for the periods indicated (dollars in millions): Three Months Ended June 30, Nine Months Ended June 30, 2019 2018 2019 2018 Gain (loss) on fair value of interest rate swaps $ 53 $ (21 ) $ 139 $ (100 ) Gain (loss) on fair value of hedged fixed-rate debt (53 ) 21 (139 ) 100 Net gain (loss) recorded in interest on borrowings $ — $ — $ — $ —
Schedule of Fair Value of Outstanding Derivatives Designated as Hedging Instruments in the Condensed Consolidated Balance Sheets	The following table summarizes the classification and the fair value of outstanding derivatives designated as hedging instruments on the Condensed Consolidated Balance Sheets (dollars in millions): June 30, September 30, Pay-variable interest rate swaps designated as fair value hedges: Other assets $ 45 $ 2 Accounts payable and other liabilities $ — $ (96 )
Schedule of Debt	Key information about the committed and/or uncommitted lines of credit is summarized in the following table (dollars in millions): Borrower Subsidiary Committed Facility Uncommitted Facility (1) Termination Date TD Ameritrade Clearing, Inc. $1,200 $300 March 1, 2022 TD Ameritrade, Inc. N/A $300 March 1, 2022 TD Ameritrade Futures & Forex LLC $45 N/A August 11, 2021 (1) The Parent is permitted, but under no obligation, to make loans under uncommitted facilities.

Capital Requirements (Tables)

Capital Requirements (Tables)	9 Months Ended
	Jun. 30, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Net Capital and Net Capital Requirements for Company's Broker-dealer Subsidiaries	Net capital and net capital requirements for the Company's broker-dealer subsidiaries are summarized in the following tables (dollars in millions): TD Ameritrade Clearing, Inc. Date Net Capital Required Net Capital (2% of Aggregate Debit Balances) Net Capital in Excess of Required Net Capital Ratio of Net Capital to Aggregate Debit Balances June 30, 2019 $ 2,980 $ 479 $ 2,501 12.44 % September 30, 2018 $ 2,831 $ 525 $ 2,306 10.79 % TD Ameritrade, Inc. Date Net Capital Required Net Capital (Minimum Dollar Requirement) Net Capital in Excess of Required Net Capital June 30, 2019 $ 218 $ 0.25 $ 218 September 30, 2018 $ 181 $ 0.25 $ 181
Adjusted Net Capital and Adjusted Net Capital Requirements for Company's FCM and FDM Subsidiary	Adjusted net capital and adjusted net capital requirements for the Company's FCM and FDM subsidiary are summarized in the following table (dollars in millions): TD Ameritrade Futures & Forex LLC Date Adjusted Net Capital Required Adjusted Net Capital ($20 Million Plus 5% of All Foreign Exchange Liabilities Owed to Forex Clients in Excess of $10 Million) Adjusted Net Capital in Excess of Required Adjusted Net Capital June 30, 2019 $ 130 $ 23 $ 107 September 30, 2018 $ 129 $ 23 $ 106

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Summary of Collateral Available, Loaned or Repledged	The following table summarizes the fair values of client margin securities and stock borrowings that were available to the Company to utilize as collateral on various borrowings or for other purposes, and the amount of that collateral loaned or repledged by the Company (dollars in billions): June 30, September 30, Client margin securities $ 29.0 $ 31.4 Stock borrowings 1.3 0.8 Total collateral available $ 30.3 $ 32.2 Collateral loaned $ 3.1 $ 2.9 Collateral repledged 4.1 6.3 Total collateral loaned or repledged $ 7.2 $ 9.2
Summary of Cash Deposited with and Securities Pledged to Clearinghouses	The following table summarizes cash deposited with and securities pledged to clearinghouses by the Company (dollars in millions): Assets Condensed Consolidated Balance Sheet Classification June 30, September 30, Cash Receivable from brokers, dealers and clearing organizations $ 461 $ 545 U.S. government debt securities Securities owned, at fair value 163 50 Total $ 624 $ 595

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	9 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Hierarchy for Assets and Liabilities Measured on Recurring Basis	The following tables present the Company's fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of June 30, 2019 and September 30, 2018 (dollars in millions): June 30, 2019 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market mutual funds $ 2,533 $ — $ — $ 2,533 Investments segregated and on deposit for regulatory purposes: U.S. government debt securities — 2,847 — 2,847 U.S. government agency mortgage-backed securities — 767 — 767 Subtotal - Investments segregated and on deposit for regulatory purposes — 3,614 — 3,614 Securities owned: U.S. government debt securities — 313 — 313 Other 1 4 — 5 Subtotal - Securities owned 1 317 — 318 Investments available-for-sale: U.S. government debt securities — 1,129 — 1,129 Other assets: Pay-variable interest rate swaps (1) — 45 — 45 U.S. government debt securities — 1 — 1 Subtotal - Other assets — 46 — 46 Total assets at fair value $ 2,534 $ 5,106 $ — $ 7,640 Liabilities: Accounts payable and other liabilities: Securities sold, not yet purchased: Equity securities $ 1 $ — $ — $ 1 (1) See " Fair Value Hedging " in Note 7 for details. September 30, 2018 Level 1 Level 2 Level 3 Fair Value Assets: Cash equivalents: Money market mutual funds $ 2,373 $ — $ — $ 2,373 Investments segregated and on deposit for regulatory purposes: U.S. government debt securities — 225 — 225 U.S. government agency mortgage-backed securities — 1,302 — 1,302 Subtotal - Investments segregated and on deposit for regulatory purposes — 1,527 — 1,527 Securities owned: U.S. government debt securities — 149 — 149 Other 1 6 — 7 Subtotal - Securities owned 1 155 — 156 Investments available-for-sale: U.S. government debt securities — 484 — 484 Other assets: Pay-variable interest rate swaps (1) — 2 — 2 U.S. government debt securities — 1 — 1 Auction rate securities — — 1 1 Subtotal - Other assets — 3 1 4 Total assets at fair value $ 2,374 $ 2,169 $ 1 $ 4,544 Liabilities: Accounts payable and other liabilities: Pay-variable interest rate swaps (1) $ — $ 96 $ — $ 96 (1) See " Fair Value Hedging " in Note 7 for details.

Offsetting Assets and Liabili_2

Offsetting Assets and Liabilities (Tables)	9 Months Ended
	Jun. 30, 2019
Offsetting [Abstract]
Effect of Rights of Setoff Associated with Company's Recognized Assets and Liabilities	The following tables present information about the potential effect of rights of setoff associated with the Company's recognized assets and liabilities as of June 30, 2019 and September 30, 2018 (dollars in millions): June 30, 2019 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet Gross Amounts of Recognized Assets and Liabilities Gross Amounts Offset in the Condensed Consolidated Balance Sheet Net Amounts Presented in the Condensed Consolidated Balance Sheet Financial Instruments (5) Collateral Received or Pledged (Including Cash) (6) Net Amount (7) Assets: Investments segregated and on deposit for regulatory purposes: Reverse repurchase agreements $ 500 $ — $ 500 $ — $ (500 ) $ — Receivable from brokers, dealers and clearing organizations: Deposits paid for securities borrowed (1) 1,285 — 1,285 (30 ) (1,234 ) 21 Other assets: Pay-variable interest rate swaps 45 — 45 (45 ) — — Total $ 1,830 $ — $ 1,830 $ (75 ) $ (1,734 ) $ 21 Liabilities: Payable to brokers, dealers and clearing organizations: Deposits received for securities loaned (2)(3) $ 3,124 $ — $ 3,124 $ (30 ) $ (2,822 ) $ 272 September 30, 2018 Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet Gross Amounts of Recognized Assets and Liabilities Gross Amounts Offset in the Condensed Consolidated Balance Sheet Net Amounts Presented in the Condensed Consolidated Balance Sheet Financial Instruments (5) Collateral Received or Pledged (Including Cash) (6) Net Amount (7) Assets: Investments segregated and on deposit for regulatory purposes: Reverse repurchase agreements $ 500 $ — $ 500 $ — $ (500 ) $ — Receivable from brokers, dealers Deposits paid for securities borrowed (1) 803 — 803 (41 ) (744 ) 18 Other assets: Pay-variable interest rate swaps 2 — 2 (2 ) — — Total $ 1,305 $ — $ 1,305 $ (43 ) $ (1,244 ) $ 18 Liabilities: Payable to brokers, dealers and clearing organizations: Deposits received for securities loaned (2)(3) $ 2,914 $ — $ 2,914 $ (43 ) $ (2,544 ) $ 327 Securities sold under agreements to repurchase ( 4 ) 96 — 96 (96 ) — — Accounts payable and other liabilities: Pay-variable interest rate swaps 96 — 96 (82 ) — 14 Total $ 3,106 $ — $ 3,106 $ (221 ) $ (2,544 ) $ 341 (1) Included in the gross amounts of deposits paid for securities borrowed is $394 million and $462 million as of June 30, 2019 and September 30, 2018 , respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of cash to the Company. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with securities borrowing transactions and how the Company mitigates those risks. (2) Included in the gross amounts of deposits received for securities loaned is $2.26 billion and $2.01 billion as of June 30, 2019 and September 30, 2018 , respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of securities to the Company. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with securities lending transactions and how the Company mitigates those risks. (3) Substantially all of the Company's securities lending transactions have a continuous contractual term and, upon notice by either party, may be terminated within two business days. The following table summarizes the Company's gross liability for securities lending transactions by the class of securities loaned (dollars in millions): June 30, September 30, Deposits received for securities loaned: Equity securities $ 2,681 $ 2,583 Exchange-traded funds 283 223 Real estate investment trusts 83 19 Closed-end funds 62 74 Other 15 15 Total $ 3,124 $ 2,914 (4) The collateral pledged includes available-for-sale U.S. government debt securities at fair value. All of the Company's repurchase agreements have a remaining contractual maturity of less than 90 days and, upon default by either party, may be terminated at the option of the non-defaulting party. See "General Contingencies" in Note 9 for a discussion of the potential risks associated with repurchase agreements and how the Company mitigates those risks. (5) Amounts represent recognized assets and liabilities that are subject to enforceable master agreements with rights of setoff. (6) Represents the fair value of collateral the Company had received or pledged under enforceable master agreements, limited for table presentation purposes to the net amount of the recognized assets due from or liabilities due to each counterparty. At June 30, 2019 and September 30, 2018 , the Company had received total collateral with a fair value of $1.82 billion and $1.30 billion , respectively, and pledged total collateral with a fair value of $2.85 billion and $2.76 billion , respectively. (7) Represents the amount for which, in the case of net recognized assets, the Company had not received collateral, and in the case of net recognized liabilities, the Company had not pledged collateral.
Disaggregation of Gross Secured Lending Transactions	The following table summarizes the Company's gross liability for securities lending transactions by the class of securities loaned (dollars in millions): June 30, September 30, Deposits received for securities loaned: Equity securities $ 2,681 $ 2,583 Exchange-traded funds 283 223 Real estate investment trusts 83 19 Closed-end funds 62 74 Other 15 15 Total $ 3,124 $ 2,914

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Other Comprehensive Income (Loss)	The following tables present the net change in fair value recorded for each component of other comprehensive income (loss) before and after income tax for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Investments available-for-sale: Unrealized gain (loss) $ 17 $ (4 ) $ 13 $ (2 ) $ — $ (2 ) Net change in investments available-for-sale 17 (4 ) 13 (2 ) — (2 ) Cash flow hedging instruments: Reclassification adjustment for portion of realized loss amortized to net income (1) 1 (1 ) — 1 — 1 Net change in cash flow hedging instruments 1 (1 ) — 1 — 1 Other comprehensive income (loss) $ 18 $ (5 ) $ 13 $ (1 ) $ — $ (1 ) Nine Months Ended June 30, 2019 2018 Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Investments available-for-sale: Unrealized gain (loss) $ 42 $ (10 ) $ 32 $ (8 ) $ 1 $ (7 ) Reclassification adjustment for realized loss included in net income (2) — — — 11 (4 ) 7 Net change in investments available-for-sale 42 (10 ) 32 3 (3 ) — Cash flow hedging instruments: Reclassification adjustment for portion of realized loss amortized to net income (1) 3 (1 ) 2 3 — 3 Net change in cash flow hedging instruments 3 (1 ) 2 3 — 3 Other comprehensive income $ 45 $ (11 ) $ 34 $ 6 $ (3 ) $ 3 (1) The before tax reclassification amounts and related tax effects are included in interest on borrowings and provision for income taxes, respectively, on the Condensed Consolidated Statements of Income. (2) The before tax reclassification amount and the related tax effect are included in loss on sale of investments and provision for income taxes, respectively, on the Condensed Consolidated Statements of Income.
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents after-tax changes in each component of accumulated other comprehensive income (loss) for the periods indicated (dollars in millions): Three Months Ended June 30, Nine Months Ended June 30, 2019 2018 2019 2018 Investments available-for-sale: Beginning balance $ 12 $ (3 ) $ (7 ) $ (5 ) Other comprehensive income (loss) before reclassifications 13 (2 ) 32 (7 ) Amounts reclassified from accumulated other comprehensive income (loss) — — — 7 Current period change 13 (2 ) 32 — Ending balance $ 25 $ (5 ) $ 25 $ (5 ) Cash flow hedging instruments: Beginning balance $ (18 ) $ (18 ) $ (20 ) $ (20 ) Amounts reclassified from accumulated other comprehensive income (loss) — 1 2 3 Ending balance $ (18 ) $ (17 ) $ (18 ) $ (17 ) Total accumulated other comprehensive income (loss): Beginning balance $ (6 ) $ (21 ) $ (27 ) $ (25 ) Current period change 13 (1 ) 34 3 Ending balance $ 7 $ (22 ) $ 7 $ (22 )

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Schedule of Related Party Transactions	The following tables summarize revenues and expenses resulting from transactions with TD and its affiliates for the periods indicated (dollars in millions): Revenues from TD and its Affiliates Condensed Consolidated Statement of Income Classification Three Months Ended June 30, Nine Months Ended June 30, Description 2019 2018 2019 2018 Insured Deposit Account Agreement Bank deposit account fees $ 392 $ 363 $ 1,193 $ 1,056 Order Routing Agreement (1) Other revenues 6 1 17 3 Other Various 2 7 19 21 Total revenues $ 400 $ 371 $ 1,229 $ 1,080 Expenses to TD and its Affiliates Condensed Consolidated Statement of Income Classification Three Months Ended June 30, Nine Months Ended June 30, Description 2019 2018 2019 2018 Order Routing Agreement (1) Other expense $ 4 N/A $ 13 N/A Other Various 3 2 6 6 Total expenses $ 7 $ 2 $ 19 $ 6 (1) Prior to fiscal year 2019, the Company accounted for revenues associated with the Order Routing Agreement between the Company and an affiliate of TD on a net basis through other revenues. Following the adoption of the new revenue recognition standard (ASU 2014-09) on October 1, 2018, the Company began accounting for Order Routing Agreement revenues on a gross basis. The Company adopted the new guidance using the modified retrospective approach, which requires the standard be applied only to the most current period presented; therefore, the prior period has not been adjusted to reflect the current period presentation. See "Recently Adopted Accounting Pronouncements" in Note 1 for additional details regarding the amended guidance. The following table summarizes the classification and amount of receivables from and payables to TD and its affiliates on the Condensed Consolidated Balance Sheets resulting from related party transactions (dollars in millions): June 30, September 30, Assets: Receivable from affiliates $ 127 $ 151 Liabilities: Payable to brokers, dealers and clearing organizations $ 23 $ 47 Payable to affiliates 3 7 Accounts payable and other liabilities 2 —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The financial statement line items affected by the adoption of ASU 2014-09 are as follows (dollars in millions): As of June 30, 2019 Condensed Consolidated Balance Sheet As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Assets: Other assets $ 285 $ 255 $ 30 Liabilities: Deferred income taxes 219 212 7 Stockholders' equity: Retained earnings 8,194 8,171 23 Three Months Ended June 30, 2019 Condensed Consolidated Statement of Income As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Revenues: Other revenues $ 59 $ 40 $ 19 Operating expenses: Employee compensation and benefits 325 323 2 Clearing and execution costs 59 47 12 Other 61 54 7 Provision for income taxes 188 188 — Net income 555 557 (2 ) Earnings per share — diluted $ 1.00 $ 1.01 $ (0.01 ) Nine Months Ended June 30, 2019 Condensed Consolidated Statement of Income As Reported Balances Without Adoption of ASU 2014-09 Effect of Change Higher/(Lower) Revenues: Other revenues $ 126 $ 82 $ 44 Operating expenses: Employee compensation and benefits 982 975 7 Clearing and execution costs 161 140 21 Other 142 119 23 Provision for income taxes 530 532 (2 ) Net income 1,658 1,663 (5 ) Earnings per share — diluted $ 2.96 $ 2.97 $ (0.01 ) Balance at September 30, 2018 Adjustments from Adoption of ASU 2014-09 Balance at October 1, 2018 Assets: Other assets $ 212 $ 37 $ 249 Liabilities: Deferred income taxes 177 9 186 Stockholders' equity: Retained earnings 7,011 28 7,039
Disaggregation of Revenue	The following tables set forth the disaggregation of the Company's revenue by major source for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 % Change Revenues: Transaction-based revenues: Commissions $ 320 $ 334 (4 )% Order routing revenue 117 119 (2 )% Other 40 37 8 % Total transaction-based revenues 477 490 Asset-based revenues: Bank deposit account fees 421 387 9 % Net interest revenue 383 332 15 % Investment product fees 151 140 8 % Total asset-based revenues 955 859 Other revenues 59 33 79 % Net revenues $ 1,491 $ 1,382 Nine Months Ended June 30, 2019 2018 % Change Revenues: Transaction-based revenues: Commissions $ 1,010 $ 1,042 (3 )% Order routing revenue 365 342 7 % Other 125 103 21 % Total transaction-based revenues 1,500 1,487 Asset-based revenues: Bank deposit account fees 1,280 1,149 11 % Net interest revenue 1,120 916 22 % Investment product fees 431 414 4 % Total asset-based revenues 2,831 2,479 Other revenues 126 88 43 % Net revenues $ 4,457 $ 4,054 The following tables present the significant components of investment product fees for the periods indicated (dollars in millions): Three Months Ended June 30, 2019 2018 % Change Investment product fees: Mutual fund service fees $ 73 $ 63 16 % Investment program fees 70 70 0 % Other 8 7 14 % Total investment product fees $ 151 $ 140 Nine Months Ended June 30, 2019 2018 % Change Investment product fees: Mutual funds service fees $ 208 $ 186 12 % Investment program fees 199 202 (1 )% Other 24 26 (8 )% Total investment product fees $ 431 $ 414
Contract with Customer, Asset and Liability	The following table presents the opening and closing balances of the Company's receivables from contracts with clients that are within the scope of ASC 606 on the Condensed Consolidated Balance Sheets (dollars in millions): Contract Balances Receivable from Clients Receivable from Affiliates Other Receivables Total Receivables from Contracts with Clients Opening balance, October 1, 2018 $ 16 $ 7 $ 115 $ 138 Closing balance, June 30, 2019 17 7 127 151 Increase $ 1 $ — $ 12 $ 13

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ in Millions	Jun. 28, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Oct. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain on business-related divestiture	$ 60	$ 60	$ 0	$ 60	$ 0
Decrease in cash flows from operating activities				$ (5,773)	5,000
ASU 2016-18 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Decrease in cash flows from operating activities					$ 5,100
Forecast [Member] | ASU 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percent of total assets for initial recognition of right-of-use asset and lease liability						1.00%

Cash, Cash Equivalents, Restr_3

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - Summary of Cash and Cash Equivalents (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 2,953	$ 2,690
Broker-dealer subsidiaries [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	1,715	2,094
Corporate [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	931	342
Trust company subsidiary [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	202	124
Futures commission merchant and forex dealer member subsidiary [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	87	89
Investment advisory subsidiaries [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 18	$ 41

Cash, Cash Equivalents, Restr_4

Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents - Reconciliation of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,953	$ 2,690
Restricted cash and restricted cash equivalents included in cash and investments segregated and on deposit for regulatory purposes	6,332	1,858
Total cash, cash equivalents, restricted cash and restricted cash equivalents shown in the Condensed Consolidated Statements of Cash Flows	$ 9,285	$ 4,548	$ 4,544	$ 9,760

Cash and Investments Segregat_3

Cash and Investments Segregated and on Deposit for Regulatory Purposes (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	$ 7,124	$ 3,185
Cash in demand deposit accounts [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	2,861	956
U.S. government debt securities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	2,822	200
U.S. government agency mortgage-backed securities [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	767	1,302
Reverse repurchase agreements (collateralized by U.S. government debt securities) [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	500	500
Cash on deposit with futures commission merchants [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	149	202
U.S. government debt securities on deposit with futures commission merchant [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and investments segregated and on deposit for regulatory purposes	$ 25	$ 25

Investments Available-for-Sal_3

Investments Available-for-Sale - Schedule of Amortized Cost and Fair Value of Available-for-Sale Securities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 1,129	$ 484
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,096	493
Gross Unrealized Gains	33	0
Gross Unrealized Losses	0	(9)
Fair Value	$ 1,129	$ 484

Investments Available-for-Sal_4

Investments Available-for-Sale - Narrative (Details) $ in Millions	Sep. 30, 2018USD ($)
Investments, Debt and Equity Securities [Abstract]
Securities pledged as collateral for repurchase agreements	$ 98

Investments Available-for-Sal_5

Investments Available-for-Sale - Schedule of Contractual Maturities of Available-for-Sale Securities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Fair Value
Fair Value	$ 1,129	$ 484
US Treasury Securities [Member]
Amortized Cost
Due within one to five years	384
Due within five to ten years	712
Amortized Cost	1,096	493
Fair Value
Due within one to five years	407
Due within five to ten years	722
Fair Value	$ 1,129	$ 484

Exit Liabilities - Summary of t

Exit Liabilities - Summary of the Activity in Exit Liabilities During the Period (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Reserve [Roll Forward]
Beginning balance	$ 8	$ 151	$ 69	$ 138
Exit liabilities assumed - post closing adjustments				9
Costs incurred and charged to expense	2	48	4	387
Costs paid or otherwise settled	(2)	(130)	(65)	(465)
Ending balance	8	69	8	69
Severance Pay and Other Termination Benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	5	113	21	138
Exit liabilities assumed - post closing adjustments				0
Costs incurred and charged to expense	2	31	6	209
Costs paid or otherwise settled	(2)	(106)	(22)	(309)
Ending balance	5	38	5	38
Contract Termination and Other Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	3	38	48	0
Exit liabilities assumed - post closing adjustments				9
Costs incurred and charged to expense	0	17	(2)	178
Costs paid or otherwise settled	0	(24)	(43)	(156)
Ending balance	$ 3	$ 31	$ 3	$ 31

Exit Liabilities - Summary of_2

Exit Liabilities - Summary of the Cumulative Acquisition-Related Exit Costs (Details) - Scottrade [Member] $ in Millions	21 Months Ended
	Jun. 30, 2019USD ($)
Restructuring Cost and Reserve [Line Items]
Exit liabilities assumed in business acquisition	$ 109
Total cumulative exit liabilities assumed and acquisition-related exit costs incurred	588
Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	267
Clearing And Execution Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	1
Communications [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	1
Occupancy and Equipment Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	7
Professional Services [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	30
Other Operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	171
Other Non-operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	2
Severance Pay and Other Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Exit liabilities assumed in business acquisition	100
Total cumulative exit liabilities assumed and acquisition-related exit costs incurred	367
Severance Pay and Other Termination Benefits [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	267
Severance Pay and Other Termination Benefits [Member] | Clearing And Execution Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Severance Pay and Other Termination Benefits [Member] | Communications [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Severance Pay and Other Termination Benefits [Member] | Occupancy and Equipment Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Severance Pay and Other Termination Benefits [Member] | Professional Services [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Severance Pay and Other Termination Benefits [Member] | Other Operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Severance Pay and Other Termination Benefits [Member] | Other Non-operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Contract Termination and Other Costs [Member]
Restructuring Cost and Reserve [Line Items]
Exit liabilities assumed in business acquisition	9
Total cumulative exit liabilities assumed and acquisition-related exit costs incurred	221
Contract Termination and Other Costs [Member] | Employee Compensation and Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	0
Contract Termination and Other Costs [Member] | Clearing And Execution Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	1
Contract Termination and Other Costs [Member] | Communications [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	1
Contract Termination and Other Costs [Member] | Occupancy and Equipment Costs [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	7
Contract Termination and Other Costs [Member] | Professional Services [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	30
Contract Termination and Other Costs [Member] | Other Operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	171
Contract Termination and Other Costs [Member] | Other Non-operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Cumulative acquisition-related exit costs incurred since the date of acquisition	$ 2

Exit Liabilities - Additional I

Exit Liabilities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Exit liabilities recorded during the period	$ 2	$ 48	$ 4	$ 387

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Income Tax Contingency [Line Items]
Effective income tax rate	24.20%	20.30%
Net favorable resolutions of state income tax matters	$ 18	$ 10
Favorable tax benefits resulting from vesting of equity-based compensation	$ 3	$ 5
Net favorable per share impact on earnings	$ 0.04	$ 0.17
Net favorable deferred income tax adjustment related to Tax Cuts and Jobs Act		$ 71
Favorable benefit resulting from selectively accelerating certain deductions to leverage higher 2017 tax rates		21
Unfavorable remeasurement of uncertain tax positions related to federal incentives		$ 9
Pre-Tax Cuts and Jobs Act [Member]
Income Tax Contingency [Line Items]
U.S. federal corporate income tax rate		35.00%
Post-Tax Cuts and Jobs Act [Member]
Income Tax Contingency [Line Items]
U.S. federal corporate income tax rate		21.00%

Long-term Debt and Other Borr_3

Long-term Debt and Other Borrowings - Schedule of Long-Term Debt and Other Borrowings (Details) - USD ($)	Jun. 30, 2019	Oct. 30, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Face Value			$ 2,646,000,000
Unamortized Discounts and Debt Issuance Costs			(17,000,000)
Fair Value Adjustment			(94,000,000)
Net Carrying Value			2,535,000,000
Senior Notes [Member]
Debt Instrument [Line Items]
Face Value	$ 3,550,000,000		2,550,000,000
Unamortized Discounts and Debt Issuance Costs	(21,000,000)		(17,000,000)
Fair Value Adjustment	45,000,000		(94,000,000)
Net Carrying Value	3,574,000,000		2,439,000,000
Senior Notes [Member] | 5.600% Notes due 2019 [Member]
Debt Instrument [Line Items]
Face Value	500,000,000		500,000,000
Unamortized Discounts and Debt Issuance Costs	0		(1,000,000)
Fair Value Adjustment	2,000,000		2,000,000
Net Carrying Value	$ 502,000,000		$ 501,000,000
Interest rate, stated percentage	5.60%		5.60%
Senior Notes [Member] | Variable-rate Notes due 2021 [Member]
Debt Instrument [Line Items]
Face Value	$ 600,000,000	$ 600,000,000
Unamortized Discounts and Debt Issuance Costs	(3,000,000)
Fair Value Adjustment	0
Net Carrying Value	597,000,000
Senior Notes [Member] | 2.950% Notes due 2022 [Member]
Debt Instrument [Line Items]
Face Value	750,000,000		$ 750,000,000
Unamortized Discounts and Debt Issuance Costs	(3,000,000)		(4,000,000)
Fair Value Adjustment	4,000,000		(27,000,000)
Net Carrying Value	$ 751,000,000		$ 719,000,000
Interest rate, stated percentage	2.95%		2.95%
Senior Notes [Member] | 3.75% Notes due 2024 [Member]
Debt Instrument [Line Items]
Face Value	$ 400,000,000	$ 400,000,000
Unamortized Discounts and Debt Issuance Costs	(4,000,000)
Fair Value Adjustment	0
Net Carrying Value	$ 396,000,000
Interest rate, stated percentage	3.75%	3.75%
Senior Notes [Member] | 3.625% Notes due 2025 [Member]
Debt Instrument [Line Items]
Face Value	$ 500,000,000		$ 500,000,000
Unamortized Discounts and Debt Issuance Costs	(3,000,000)		(3,000,000)
Fair Value Adjustment	19,000,000		(17,000,000)
Net Carrying Value	$ 516,000,000		$ 480,000,000
Interest rate, stated percentage	3.625%		3.625%
Senior Notes [Member] | 3.300% Notes due 2027 [Member]
Debt Instrument [Line Items]
Face Value	$ 800,000,000		$ 800,000,000
Unamortized Discounts and Debt Issuance Costs	(8,000,000)		(9,000,000)
Fair Value Adjustment	20,000,000		(52,000,000)
Net Carrying Value	$ 812,000,000		$ 739,000,000
Interest rate, stated percentage	3.30%		3.30%
Securities Sold Under Agreements to Repurchase [Member]
Debt Instrument [Line Items]
Face Value			$ 96,000,000
Unamortized Discounts and Debt Issuance Costs			0
Fair Value Adjustment			0
Net Carrying Value	$ 0		$ 96,000,000

Long-term Debt and Other Borr_4

Long-term Debt and Other Borrowings - Fiscal Year Maturities on Long-term Debt Outstanding (Details) $ in Millions	Jun. 30, 2019USD ($)
Debt Disclosure [Abstract]
2019 Remaining	$ 0
2020	500
2021	0
2022	1,350
2023	0
Thereafter	1,700
Total	$ 3,550

Long-term Debt and Other Borr_5

Long-term Debt and Other Borrowings - Senior Notes, Lines of Credit and Securities Sold Under Agreements to Repurchase - Additional Information (Details)	9 Months Ended
	Jun. 30, 2019USD ($)bank	Oct. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Debt Instrument [Line Items]
Face Value			$ 2,646,000,000
Borrowings outstanding			2,535,000,000
Line of Credit [Member] | TD Ameritrade Clearing, Inc. [Member]
Debt Instrument [Line Items]
Number of unaffiliated banks | bank	2
Borrowings outstanding	$ 0		0
Securities Sold Under Agreements to Repurchase [Member]
Debt Instrument [Line Items]
Face Value			96,000,000
Borrowings outstanding	0		$ 96,000,000
Debt instrument, effective interest rate			2.35%
Senior Notes [Member]
Debt Instrument [Line Items]
Face Value	3,550,000,000		$ 2,550,000,000
Borrowings outstanding	3,574,000,000		$ 2,439,000,000
Variable-rate Notes due 2021 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Face Value	600,000,000	$ 600,000,000
Borrowings outstanding	597,000,000
3.75% Notes due 2024 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Face Value	$ 400,000,000	$ 400,000,000
Interest rate, stated percentage	3.75%	3.75%
Borrowings outstanding	$ 396,000,000
Senior Notes Due 2021 And 2024 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage	100.00%
Debt instrument, redemption price, basis spread on US treasury rate	0.15%
LIBOR [Member] | Variable-rate Notes due 2021 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Description of basis spread on variable rate	three-month LIBOR
Debt instrument, basis spread on variable rate	0.43%

Long-term Debt and Other Borr_6

Long-term Debt and Other Borrowings - Fair Value Hedging - Additional Information (Details) - Senior Notes [Member]	9 Months Ended
	Jun. 30, 2019
Debt Instrument [Line Items]
Weighted-average effective interest rate	3.72%
LIBOR [Member] | Pay Variable Interest Rate Swap [Member]
Debt Instrument [Line Items]
Description of basis spread on variable rate	three-month LIBOR
2019 Notes [Member] | LIBOR [Member] | Pay Variable Interest Rate Swap [Member]
Debt Instrument [Line Items]
Basis spread on variable rate, percentage	2.3745%
2022 Notes [Member] | LIBOR [Member] | Pay Variable Interest Rate Swap [Member]
Debt Instrument [Line Items]
Basis spread on variable rate, percentage	0.9486%
2025 Notes [Member] | LIBOR [Member] | Pay Variable Interest Rate Swap [Member]
Debt Instrument [Line Items]
Basis spread on variable rate, percentage	1.1022%
2027 Notes [Member] | LIBOR [Member] | Pay Variable Interest Rate Swap [Member]
Debt Instrument [Line Items]
Basis spread on variable rate, percentage	1.034%

Long-term Debt and Other Borr_7

Long-term Debt and Other Borrowings - Gains and Losses Resulting from Changes in Fair Value of Interest Rate Swaps and Hedged Fixed Rate Debt (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Disclosure [Abstract]
Gain (loss) on fair value of interest rate swaps	$ 53	$ (21)	$ 139	$ (100)
Gain (loss) on fair value of hedged fixed-rate debt	(53)	21	(139)	100
Net gain (loss) recorded in interest on borrowings	$ 0	$ 0	$ 0	$ 0

Long-term Debt and Other Borr_8

Long-term Debt and Other Borrowings - Fair Value of Outstanding Derivatives Designated as Hedging Instruments (Details) - Pay Variable Interest Rate Swap [Member] - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Other assets [Member]
Derivatives, Fair Value [Line Items]
Fair value of outstanding derivative assets designated as hedging instruments in the Consolidated Balance Sheets	$ 45	$ 2
Accounts payable and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value of outstanding derivative liabilities designated as hedging instruments in the Consolidated Balance Sheets	$ 0	$ (96)

Long-term Debt and Other Borr_9

Long-term Debt and Other Borrowings - Balance Sheet Impact of Hedging Instruments - Additional Information (Details) - Pay Variable Interest Rate Swap [Member] - Cash [Member] - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Pledged collateral from interest rate swap counterparty, aggregate fair value	$ 45	$ 10
Pledged collateral to interest rate swap counterparty, aggregate fair value		$ 82

Long-term Debt and Other Bor_10

Long-term Debt and Other Borrowings - Credit Agreements - Additional Information (Details)	9 Months Ended
	Jun. 30, 2019USD ($)facility	May 16, 2019USD ($)	Sep. 30, 2018USD ($)	May 17, 2018USD ($)	Apr. 21, 2017USD ($)
Intercompany Credit Facility [Member]
Debt Instrument [Line Items]
Borrowings outstanding	$ 0		$ 0
Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity					$ 300,000,000
Credit facility, commitment fee percentage	0.125%
Borrowings outstanding	$ 0		0
ABR Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.125%
ABR Loans [Member] | Parent Company [Member] | Fed Funds Effective Rate Overnight Index Swap Rate [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
ABR Loans [Member] | Parent Company [Member] | Eurodollar [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
Eurodollar Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.125%
Minimum [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.08%
Minimum [Member] | ABR Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.00%
Minimum [Member] | Eurodollar Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.875%
Maximum [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.20%
Maximum [Member] | ABR Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
Maximum [Member] | Eurodollar Loans [Member] | Parent Company [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.50%
TD Ameritrade Clearing, Inc. [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 1,450,000,000
Borrowings outstanding	$ 0		$ 0
Number of credit facilities | facility	2
TD Ameritrade Clearing, Inc. [Member] | Federal Funds Rate Loans [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
TD Ameritrade Clearing, Inc. [Member] | Revolving Facility, 600 Million Dollars [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity					$ 600,000,000
Credit facility, commitment fee percentage	0.10%
TD Ameritrade Clearing, Inc. [Member] | Revolving Facility, 850 Million Dollars [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity		$ 850,000,000		$ 850,000,000
Credit facility, commitment fee percentage	0.08%
TD Ameritrade Clearing, Inc. [Member] | TDAC Eurodollar Loans [Member] | LIBOR [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
TD Ameritrade Clearing, Inc. [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.07%
TD Ameritrade Clearing, Inc. [Member] | Minimum [Member] | Federal Funds Rate Loans [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%
TD Ameritrade Clearing, Inc. [Member] | Minimum [Member] | Eurodollar Loans [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%
TD Ameritrade Clearing, Inc. [Member] | Minimum [Member] | Revolving Facility, 850 Million Dollars [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.06%
TD Ameritrade Clearing, Inc. [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.175%
TD Ameritrade Clearing, Inc. [Member] | Maximum [Member] | Federal Funds Rate Loans [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.25%
TD Ameritrade Clearing, Inc. [Member] | Maximum [Member] | Eurodollar Loans [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.25%
TD Ameritrade Clearing, Inc. [Member] | Maximum [Member] | Revolving Facility, 850 Million Dollars [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, commitment fee percentage	0.125%

Long-term Debt and Other Bor_11

Long-term Debt and Other Borrowings - Key Information of Intercompany Credit Agreements (Details) $ in Millions	Jun. 30, 2019USD ($)
TD Ameritrade Clearing, Inc. [Member] | Committed Intercompany Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 1,200
TD Ameritrade Clearing, Inc. [Member] | Uncommitted Intercompany Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	300
TD Ameritrade, Inc. [Member] | Uncommitted Intercompany Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	300
TD Ameritrade Futures & Forex LLC [Member] | Committed Intercompany Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 45

Capital Requirements - Net Capi

Capital Requirements - Net Capital and Net Capital Requirements for Company's Subsidiaries (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Sep. 30, 2018
TD Ameritrade Clearing, Inc. [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Net Capital	$ 2,980,000	$ 2,831,000
Required Net Capital (2% of Aggregate Debit Balances)	479,000	525,000
Net Capital in Excess of Required Net Capital	$ 2,501,000	$ 2,306,000
Ratio of Net Capital to Aggregate Debit Balances	12.44%	10.79%
TD Ameritrade, Inc. [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Net Capital	$ 218,000	$ 181,000
Required Net Capital (2% of Aggregate Debit Balances)	250	250
Net Capital in Excess of Required Net Capital	218,000	181,000
TD Ameritrade Futures & Forex LLC [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Adjusted Net Capital	130,000	129,000
Required Adjusted Net Capital ($20 Million Plus 5% of All Foreign Exchange Liabilities Owed to Forex Clients in Excess of $10 Million)	23,000	23,000
Adjusted Net Capital in Excess of Required Adjusted Net Capital	$ 107,000	$ 106,000

Capital Requirements - Addition

Capital Requirements - Additional Information (Details) - USD ($)	Jun. 30, 2019	Sep. 30, 2018
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Alternative net capital requirement, percentage of net capital to aggregate debit balances required for a broker-dealer to repay subordinated borrowings, pay cash dividends, or make any unsecured advances or loans to its parent company or employees	5.00%
Alternative net capital requirement, percentage of net capital to the minimum dollar requirement required for a broker-dealer to repay subordinated borrowings, pay cash dividends, or make any unsecured advances or loans to its parent company or employees	120.00%
TD Ameritrade Clearing, Inc. [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Alternative net capital requirement, dollar amount threshold	$ 1,500,000
Alternative net capital requirement, percentage of aggregate debit balances	2.00%
TD Ameritrade, Inc. [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Alternative net capital requirement, dollar amount threshold	$ 250,000
Alternative net capital requirement, percentage of aggregate debit balances	2.00%
TD Ameritrade Futures & Forex LLC [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
FCM required net capital under the Commodity Exchange Act, dollar amount threshold	$ 1,000,000
FCM required net capital under the Commodity Exchange Act, percentage of total risk margin requirements for all positions carried in client accounts	8.00%
FCM required net capital under the Commodity Exchange Act, percentage of total risk margin requirements for all positions carried in non-client accounts	8.00%
FDM required net capital under the Commodity Exchange Act, dollar amount threshold	$ 20,000,000
FDM required net capital under the Commodity Exchange Act, percentage of forex liabilities in excess of $10 million added to the dollar amount threshold	5.00%
FDM required net capital under the Commodity Exchange Act, minimum forex client liability dollar amount threshold	$ 10,000,000
FCM and FDM required net capital under the Commodity Exchange Act, required notice to CFTC, minimum percentage of adjusted net capital to the risk-based capital requirement	110.00%
FCM and FDM required net capital under the Commodity Exchange Act, required notice to CFTC, minimum percentage of adjusted net capital to the FCM's $1 million threshold	150.00%
FCM and FDM required net capital under the Commodity Exchange Act, required notice to CFTC, minimum percentage of adjusted net capital to the FDM's $20 million plus 5% of foreign exchange liabilities owed to forex clients in excess of $10 million threshold	110.00%
TD Ameritrade Trust Company [Member]
Net Capital and Net Capital Requirements For Company's Subsidiaries [Line Items]
Tier 1 capital, balance at period end	$ 88,000,000	$ 39,000,000
Amount in excess of required Tier 1 capital	$ 67,000,000	$ 18,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Jul. 09, 2019USD ($)	Mar. 13, 2019plaintiff	Jun. 30, 2019USD ($)plaintiffinvestor	Sep. 30, 2014litigation_case	May 31, 2019USD ($)	Sep. 30, 2018USD ($)
Contingencies and Commitments [Line Items]
Contingent liability for guarantees to securities clearinghouses and exchanges			$ 0			$ 0
Order Routing Matters [Member]
Contingencies and Commitments [Line Items]
Number of claims previously filed | litigation_case				6
Number of claims dismissed | litigation_case				5
Number of pending claims | litigation_case				1
Aequitas Securities Litigation [Member]
Contingencies and Commitments [Line Items]
Alleged amount of securities purchased by Company clients			140,000,000
Minimum [Member]
Contingencies and Commitments [Line Items]
Aggregate range of reasonably possible losses in excess of amounts accrued			0
Maximum [Member]
Contingencies and Commitments [Line Items]
Aggregate range of reasonably possible losses in excess of amounts accrued			$ 65,000,000
TD Ameritrade, Inc. [Member] | Order Routing Matters [Member]
Contingencies and Commitments [Line Items]
Number of claims previously filed | litigation_case				5
Scottrade, Inc. [Member] | Order Routing Matters [Member]
Contingencies and Commitments [Line Items]
Number of claims previously filed | litigation_case				1
Ciuffitelli Class Action [Member]
Contingencies and Commitments [Line Items]
Preliminary settlement between plaintiffs and Tonkon Torp Defendant					$ 14,600,000
Ciuffitelli Class Action [Member] | Aequitas Securities Litigation [Member]
Contingencies and Commitments [Line Items]
Alleged number of investors involved in the claim (more than) | investor			1,500
Alleged amount owed to investors			$ 600,000,000
Non Class Action Lawsuits [Member] | Aequitas Securities Litigation [Member]
Contingencies and Commitments [Line Items]
Number of plaintiffs | plaintiff			200
Alleged plaintiff losses plus other damages			$ 150,000,000
FINRA Arbitration [Member] | Aequitas Securities Litigation [Member]
Contingencies and Commitments [Line Items]
Number of plaintiffs | plaintiff		29
Subsequent Event [Member] | Ciuffitelli Class Action [Member]
Contingencies and Commitments [Line Items]
Preliminary settlement between plaintiffs and Tonkon Torp Defendant	$ 220,000,000
Amount of settlement to be contributed	20,000,000
Amount of settlement to be contributed by insurers	$ 12,000,000

Commitments and Contingencies_2

Commitments and Contingencies - Collateral Available, Loaned or Repledged (Details) - USD ($) $ in Billions	Jun. 30, 2019	Sep. 30, 2018
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Total collateral available	$ 30.3	$ 32.2
Collateral loaned	3.1	2.9
Collateral repledged	4.1	6.3
Total collateral loaned or repledged	7.2	9.2
Client Margin Securities [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Total collateral available	29	31.4
Stock Borrowings [Member]
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Total collateral available	$ 1.3	$ 0.8

Commitments and Contingencies_3

Commitments and Contingencies - Summary of Cash Deposited with and Securities Pledged to Clearinghouses (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]
Cash deposited and securities pledged	$ 624	$ 595
Cash [Member] | Receivable from brokers, dealers and clearing organizations [Member]
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]
Cash deposited and securities pledged	461	545
U.S. government debt securities [Member] | Securities owned, at fair value [Member]
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]
Cash deposited and securities pledged	$ 163	$ 50

Fair Value Disclosures - Fair V

Fair Value Disclosures - Fair Value Hierarchy for Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Assets:
Securities owned	$ 318	$ 156
Investments available-for-sale, at fair value	1,129	484
Recurring [Member]
Assets:
Investments segregated for regulatory purposes	3,614	1,527
Securities owned	318	156
Other assets	46	4
Total assets at fair value	7,640	4,544
Recurring [Member] | U.S. Government Debt Securities [Member]
Assets:
Investments segregated for regulatory purposes	2,847	225
Securities owned	313	149
Investments available-for-sale, at fair value	1,129	484
Other assets	1	1
Recurring [Member] | U.S. Government Agency Mortgage-Backed Securities [Member]
Assets:
Investments segregated for regulatory purposes	767	1,302
Recurring [Member] | Other Securities [Member]
Assets:
Securities owned	5	7
Recurring [Member] | Auction Rate Securities [Member]
Assets:
Other assets		1
Recurring [Member] | Equity Securities [Member]
Liabilities:
Accounts payable and other liabilities	1
Recurring [Member] | Pay Variable Interest Rate Swap [Member]
Assets:
Other assets	45	2
Liabilities:
Accounts payable and other liabilities		96
Recurring [Member] | Money Market Mutual Funds [Member]
Assets:
Cash equivalents	2,533	2,373
Recurring [Member] | Level 1 [Member]
Assets:
Securities owned	1	1
Total assets at fair value	2,534	2,374
Recurring [Member] | Level 1 [Member] | Other Securities [Member]
Assets:
Securities owned	1	1
Recurring [Member] | Level 1 [Member] | Equity Securities [Member]
Liabilities:
Accounts payable and other liabilities	1
Recurring [Member] | Level 1 [Member] | Money Market Mutual Funds [Member]
Assets:
Cash equivalents	2,533	2,373
Recurring [Member] | Level 2 [Member]
Assets:
Investments segregated for regulatory purposes	3,614	1,527
Securities owned	317	155
Other assets	46	3
Total assets at fair value	5,106	2,169
Recurring [Member] | Level 2 [Member] | U.S. Government Debt Securities [Member]
Assets:
Investments segregated for regulatory purposes	2,847	225
Securities owned	313	149
Investments available-for-sale, at fair value	1,129	484
Other assets	1	1
Recurring [Member] | Level 2 [Member] | U.S. Government Agency Mortgage-Backed Securities [Member]
Assets:
Investments segregated for regulatory purposes	767	1,302
Recurring [Member] | Level 2 [Member] | Other Securities [Member]
Assets:
Securities owned	4	6
Recurring [Member] | Level 2 [Member] | Pay Variable Interest Rate Swap [Member]
Assets:
Other assets	$ 45	2
Liabilities:
Accounts payable and other liabilities		96
Recurring [Member] | Level 3 [Member]
Assets:
Other assets		1
Total assets at fair value		1
Recurring [Member] | Level 3 [Member] | Auction Rate Securities [Member]
Assets:
Other assets		$ 1

Fair Value Disclosures - Additi

Fair Value Disclosures - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2019	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Reverse repurchase agreements, general maturity	7 days
Debt Instrument [Line Items]
Long-term debt, aggregate carrying value	$ 3,574	$ 2,439
Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt, aggregate estimated fair value	3,640	2,510
Long-term debt, aggregate carrying value	$ 3,570	$ 2,440

Offsetting Assets and Liabili_3

Offsetting Assets and Liabilities - Effect of Rights of Setoff Associated with Company's Recognized Assets and Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Offsetting Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed [Abstract]
Total recognized assets, gross	$ 1,830	$ 1,305
Total recognized assets, gross amounts offset in the balance sheet	0	0
Total recognized assets, net amounts presented in the balance sheet	1,830	1,305
Total recognized assets, gross amounts not offset in the balance sheet, financial instruments	(75)	(43)
Total recognized assets, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)	(1,734)	(1,244)
Total recognized assets, net amount	21	18
Offsetting Securities Loaned [Abstract]
Deposits received for securities loaned, gross	3,124	2,914
Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase, gross amounts not offset in the balance sheet, financial instruments		(98)
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Total recognized liabilities, gross		3,106
Total recognized liabilities, gross amounts offset in the balance sheet		0
Total recognized liabilities, net amounts presented in the balance sheet		3,106
Total recognized liabilities, gross amounts not offset in the balance sheet, financial instruments		(221)
Total recognized liabilities, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)		(2,544)
Total recognized liabilities, net amount		341
Investments segregated for regulatory purposes [Member]
Offsetting Securities Purchased under Agreements to Resell [Abstract]
Reverse repurchase agreements, gross	500	500
Reverse repurchase agreements, gross amounts offset in the balance sheet	0	0
Reverse repurchase agreements, net amounts presented in the balance sheet	500	500
Reverse repurchase agreements, gross amounts not offset in the balance sheet, financial instruments	0	0
Reverse repurchase agreements, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)	(500)	(500)
Reverse repurchase agreements, net amount	0	0
Receivable from brokers, dealers and clearing organizations [Member]
Offsetting Securities Borrowed [Abstract]
Deposits paid for securities borrowed, gross	1,285	803
Deposits paid for securities borrowed, gross amounts offset in the balance sheet	0	0
Deposits paid for securities borrowed, net amounts presented in the balance sheet	1,285	803
Deposits paid for securities borrowed, gross amounts not offset in the balance sheet, financial instruments	(30)	(41)
Deposits paid for securities borrowed, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)	(1,234)	(744)
Deposits paid for securities borrowed, net amount	21	18
Other assets [Member]
Offsetting Derivative Assets [Abstract]
Pay-variable interest rate swaps, gross	45	2
Pay-variable interest rate swaps, gross amounts offset in the balance sheet	0	0
Pay-variable interest rate swaps, net amounts presented in the balance sheet	45	2
Pay-variable interest rate swaps, gross amounts not offset in the balance sheet, financial instruments	(45)	(2)
Pay-variable interest rate swaps, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)	0	0
Pay-variable interest rate swaps, net amount	0	0
Payable to brokers, dealers and clearing organizations [Member]
Offsetting Securities Loaned [Abstract]
Deposits received for securities loaned, gross	3,124	2,914
Deposits received for securities loaned, gross amounts offset in the balance sheet	0	0
Deposits received for securities loaned, net amounts presented in the balance sheet	3,124	2,914
Deposits received for securities loaned, gross amounts not offset in the balance sheet, financial instruments	(30)	(43)
Deposits received for securities loaned, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)	(2,822)	(2,544)
Deposits received for securities loaned, net amount	$ 272	327
Securities sold under agreements to repurchase [Member]
Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase, gross		96
Securities sold under agreements to repurchase, gross amounts offset in the balance sheet		0
Securities sold under agreements to repurchase, net amounts presented in the balance sheet		96
Securities sold under agreements to repurchase, gross amounts not offset in the balance sheet, financial instruments		(96)
Securities sold under agreements to repurchase, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)		0
Securities sold under agreements to repurchase, net amount		0
Accounts payable and other liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Pay-variable rate interest rate swaps, gross		96
Pay-variable rate interest rate swaps, gross amounts offset in the balance sheet		0
Pay-variable rate interest rate swaps, net amounts presented in the balance sheet		96
Pay-variable rate interest rate swaps, gross amounts not offset in the balance sheet, financial instruments		(82)
Pay-variable rate interest rate swaps, gross amounts not offset in the balance sheet, collateral received or pledged (including cash)		0
Pay-variable rate interest rate swaps, net amount		$ 14

Offsetting Assets and Liabili_4

Offsetting Assets and Liabilities - Disaggregation of Secured Lending Transactions (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	$ 3,124	$ 2,914
Equity Securities [Member]
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	2,681	2,583
Exchange-traded Funds [Member]
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	283	223
Real Estate Investment Trusts [Member]
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	83	19
Closed-end Funds [Member]
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	62	74
Other Securities [Member]
Disaggregation of Gross Securities Lending Transactions [Line Items]
Deposits received for securities loaned, gross	$ 15	$ 15

Offsetting Assets and Liabili_5

Offsetting Assets and Liabilities - Additional Information (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Offsetting Assets And Liabilities [Line Items]
Fair value of collateral the Company has received under enforceable master agreements	$ 1,820	$ 1,300
Fair value of collateral the Company has pledged under enforceable master agreements	2,850	2,760
Transacted Through the Option Clearing Corporation [Member]
Offsetting Assets And Liabilities [Line Items]
Gross amounts of deposits paid for securities borrowed	394	462
Gross amounts of deposits received for securities loaned	$ 2,260	$ 2,010

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Net Change (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investments available-for-sale:
Unrealized gain (loss), before tax	$ 17	$ (2)	$ 42	$ (8)
Unrealized gain (loss), tax effect	(4)	0	(10)	1
Unrealized gain (loss), net of tax	13	(2)	32	(7)
Reclassification adjustment for realized losses included in net income, before tax	0	0	0	11
Reclassification adjustment for realized losses included in net income, tax effect			0	(4)
Reclassification adjustment for realized losses included in net income, net of tax			0	7
Net change in investments available-for-sale	17	(2)	42	3
Net change in investments available-for-sale, tax effect	(4)	0	(10)	(3)
Net change in investments available-for-sale, net of tax	13	(2)	32	0
Cash flow hedging instruments:
Reclassification adjustment for portion of realized loss amortized to net income, before tax	1	1	3	3
Reclassification adjustment for portion of realized loss amortized to net income, tax effect	(1)	0	(1)	0
Reclassification adjustment for portion of realized loss amortized to net income, net of tax	0	1	2	3
Net change in cash flow hedging instruments, before tax	1	1	3	3
Net change in cash flow hedging instruments, tax effect	(1)	0	(1)	0
Net change in cash flow hedging instruments, net of tax	0	1	2	3
Total other comprehensive income (loss), before tax	18	(1)	45	6
Income tax effect	(5)	0	(11)	(3)
Total other comprehensive income (loss), net of tax	$ 13	$ (1)	$ 34	$ 3

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Balance Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, value	$ 8,323	$ 7,595	$ 8,003	$ 7,247
Current period change	13	(1)	34	3
Ending balance, value	8,493	7,936	8,493	7,936
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, value	(6)	(21)	(27)	(25)
Current period change	13	(1)	34	3
Ending balance, value	7	(22)	7	(22)
Investments Available-for-sale [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, value	12	(3)	(7)	(5)
Other comprehensive income (loss) before reclassifications	13	(2)	32	(7)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0	7
Current period change	13	(2)	32	0
Ending balance, value	25	(5)	25	(5)
Cash Flow Hedging Instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, value	(18)	(18)	(20)	(20)
Amounts reclassified from accumulated other comprehensive income (loss)	0	1	2	3
Ending balance, value	$ (18)	$ (17)	$ (18)	$ (17)

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Antidilutive awards excluded from the calculation of diluted earnings per share (in shares)	0	0	0	0

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	Jul. 01, 2018	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)board_of_directors_membercomponent	Jun. 30, 2018USD ($)	Sep. 30, 2018USD ($)
Related Party Transaction [Line Items]
Number of Board of Directors members, total | board_of_directors_member				12
Payable to affiliates		$ 3,000,000		$ 3,000,000		$ 45,000,000
TD and its affiliates [Member]
Related Party Transaction [Line Items]
Percentage ownership in the Company		43.00%		43.00%
Number of Board of Directors members, designated by related party | board_of_directors_member				5
Payable to affiliates		$ 3,000,000		$ 3,000,000		7,000,000
Expenses to related parties		$ 7,000,000	$ 2,000,000	$ 19,000,000	$ 6,000,000
TD and its affiliates [Member] | Insured Deposit Account Agreement [Member]
Related Party Transaction [Line Items]
Related party transaction, agreement successive renewal term	5 years			5 years
Related party transaction, non-renewal terms, prior written notice period for termination of related party agreement by any party				2 years
Number of primary components related to the fee earned on IDA agreement | component				2
Reset frequency of adjustments required to adjust variable rate leg of interest rate swaps under current IDA Agreement				1 month
Percentage of fixed rate notional investments		83.00%		83.00%
Percentage of floating rate investments		17.00%		17.00%
Deposit amount threshold for floating-rate or fixed-rate notional investments with a maturity of up to 24 months subject to servicing fee adjustment				$ 20,000,000,000
Contingent liability carried on the condensed consolidated balance sheets for the Insured Deposit Account Agreement		$ 0		$ 0		0
TD and its affiliates [Member] | Insured Deposit Account Agreement [Member] | Minimum [Member]
Related Party Transaction [Line Items]
Servicing fee percentage				0.03%
TD and its affiliates [Member] | Insured Deposit Account Agreement [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Servicing fee percentage				0.25%
Maturity of short-term fixed-rate notional investments				24 months
TD and its affiliates [Member] | Insured Deposit Account Agreement [Member] | New Fixed Rate Notional Investments [Member]
Related Party Transaction [Line Items]
Event one, federal funds effective rate, minimum				0.75%
Term of U.S. dollar interest rate swaps				5 years
Event two, minimum rate on five-year U.S. dollar interest rate swaps for 20 consecutive business days				1.50%
Event two, number of consecutive business days required above the minimum rate on U.S. dollar interest rate swaps for reduction in rate earned by Company				20 days
Percentage used in the calculation to reduce the rate earned by the Company on new fixed-rate notional investments in the case event 1 and event 2 are both fulfilled		20.00%		20.00%
Maximum reduction to rate on new fixed-rate notional investments earned by Company in the case event 1 and event 2 are both fulfilled		0.10%		0.10%
TD and its affiliates [Member] | Insured Deposit Account Agreement Fee Example [Member]
Related Party Transaction [Line Items]
Designated deposit amount				$ 100,000,000
Term of deposits invested in fixed rate investments				5 years
Term of applicable swaps				5 years
Fixed yield for applicable LIBOR-based swaps				1.45%
Gross fixed yield earned on deposits				1.45%
TD and its affiliates [Member] | Debt Issuance Costs [Member]
Related Party Transaction [Line Items]
Expenses to related parties				$ 1,000,000
Management [Member] | Scottrade [Member]
Related Party Transaction [Line Items]
Payable to affiliates						38,000,000
TD Ameritrade Holding Corporation and TD Ameritrade Clearing, Inc. [Member] | Senior Revolving Credit Facilities [Member]
Related Party Transaction [Line Items]
Lending commitment received from related party		$ 221,000,000		$ 221,000,000		$ 257,000,000

Related Party Transactions - Su

Related Party Transactions - Summary of Revenues Resulting from Transactions with Related Parties (Details) - TD and its affiliates [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Revenues from related parties	$ 400	$ 371	$ 1,229	$ 1,080
Insured Deposit Account Agreement [Member] | Bank Deposit Account Fees [Member]
Related Party Transaction [Line Items]
Revenues from related parties	392	363	1,193	1,056
Order Routing Agreement [Member] | Other Revenues [Member]
Related Party Transaction [Line Items]
Revenues from related parties	6	1	17	3
Other [Member] | Various [Member]
Related Party Transaction [Line Items]
Revenues from related parties	$ 2	$ 7	$ 19	$ 21

Related Party Transactions - _2

Related Party Transactions - Summary of Expenses Resulting from Transactions with Related Parties (Details) - TD and its affiliates [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Expenses to related parties	$ 7	$ 2	$ 19	$ 6
Order Routing Agreement [Member] | Other Expense [Member]
Related Party Transaction [Line Items]
Expenses to related parties	4		13
Other [Member] | Various [Member]
Related Party Transaction [Line Items]
Expenses to related parties	$ 3	$ 2	$ 6	$ 6

Related Party Transactions - _3

Related Party Transactions - Summary of Classification and Amount of Receivables from and Payables to Affiliates of Company (Details) - USD ($) $ in Millions	Jun. 30, 2019	Sep. 30, 2018
Assets:
Receivable from affiliates	$ 127	$ 151
Liabilities:
Payable to brokers, dealers and clearing organizations	3,210	2,980
Payable to affiliates	3	45
TD and its affiliates [Member]
Assets:
Receivable from affiliates	127	151
Liabilities:
Payable to brokers, dealers and clearing organizations	23	47
Payable to affiliates	3	7
Accounts payable and other liabilities	$ 2	$ 0

Accelerated Stock Repurchase _2

Accelerated Stock Repurchase Agreements - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Mar. 28, 2019	Mar. 26, 2019	Mar. 05, 2019	Nov. 30, 2018	Oct. 16, 2018	Sep. 13, 2018	Mar. 05, 2019	Sep. 25, 2019
Accelerated Stock Repurchase Agreement - Mar 2019 [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Prepayment of accelerated stock repurchase agreement	$ 350
Initial delivery of shares repurchased under accelerated stock repurchase agreement (in shares)	5,600,000
Accelerated stock repurchase program, percentage of shares	80.00%
Accelerated stock repurchase program, initial price paid per share (in dollars per share)		$ 49.64
Accelerated Stock Repurchase Agreement - Nov 2018 [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Prepayment of accelerated stock repurchase agreement				$ 60
Initial delivery of shares repurchased under accelerated stock repurchase agreement (in shares)				900,000
Accelerated stock repurchase program, shares received upon settlement (in shares)			300,000
Total shares repurchased under accelerated stock repurchase agreement (in shares)							1,200,000
Accelerated stock repurchase program, final price paid per share (in dollars per share)							$ 52.12
Accelerated Stock Repurchase Agreement - Sept 2018 [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Prepayment of accelerated stock repurchase agreement						$ 150
Initial delivery of shares repurchased under accelerated stock repurchase agreement (in shares)						2,200,000
Accelerated stock repurchase program, shares received upon settlement (in shares)					600,000
Total shares repurchased under accelerated stock repurchase agreement (in shares)					2,800,000
Accelerated stock repurchase program, final price paid per share (in dollars per share)					$ 53.13
Forecast [Member] | Maximum [Member] | Accelerated Stock Repurchase Agreement - Mar 2019 [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Total shares repurchased under accelerated stock repurchase agreement (in shares)								14,100,000

Revenue Recognition - Impact of

Revenue Recognition - Impact of Adoption (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Oct. 01, 2018	Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other assets	$ 285		$ 285		$ 249	$ 212
Deferred income taxes	219		219		186	177
Retained earnings	8,194		8,194		7,039	7,011
Other revenues	59	$ 33	126	$ 88
Employee compensation and benefits	325	352	982	1,228
Clearing and execution costs	59	46	161	149
Other	61	42	142	286
Provision for income taxes	188	152	530	259
Net income	$ 555	$ 451	$ 1,658	$ 1,019
Earnings per share - diluted (in USD per share)	$ 1	$ 0.79	$ 2.96	$ 1.79
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other assets	$ 255		$ 255			212
Deferred income taxes	212		212			177
Retained earnings	8,171		8,171			$ 7,011
Other revenues	40		82
Employee compensation and benefits	323		975
Clearing and execution costs	47		140
Other	54		119
Provision for income taxes	188		532
Net income	$ 557		$ 1,663
Earnings per share - diluted (in USD per share)	$ 1.01		$ 2.97
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other assets	$ 30		$ 30		37
Deferred income taxes	7		7		9
Retained earnings	23		23		$ 28
Other revenues	19		44
Employee compensation and benefits	2		7
Clearing and execution costs	12		21
Other	7		23
Provision for income taxes	0		(2)
Net income	$ (2)		$ (5)
Earnings per share - diluted (in USD per share)	$ (0.01)		$ (0.01)

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Commissions and transaction fees	$ 477	$ 490	$ 1,500	$ 1,487
Bank deposit account fees	421	387	1,280	1,149
Net interest revenue	383	332	1,120	916
Investment product fees	151	140	431	414
Total asset-based revenues	955	859	2,831	2,479
Other revenues	59	33	126	88
Net revenues	$ 1,491	1,382	$ 4,457	4,054
Bank deposit account fees	9.00%		11.00%
Net interest revenue	15.00%		22.00%
Investment product fees	8.00%		4.00%
Other revenues	79.00%		43.00%
Commissions [Member]
Disaggregation of Revenue [Line Items]
Commissions and transaction fees	$ 320	334	$ 1,010	1,042
Transaction-based revenues	(4.00%)		(3.00%)
Order Routing Revenue [Member]
Disaggregation of Revenue [Line Items]
Commissions and transaction fees	$ 117	119	$ 365	342
Transaction-based revenues	(2.00%)		7.00%
Other Transaction-Based Revenues [Member]
Disaggregation of Revenue [Line Items]
Commissions and transaction fees	$ 40	$ 37	$ 125	$ 103
Transaction-based revenues	8.00%		21.00%

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Investment Product Fees (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Investment product fees	$ 151	$ 140	$ 431	$ 414
% Change	8.00%		4.00%
Mutual Fund Service Fees [Member]
Disaggregation of Revenue [Line Items]
Investment product fees	$ 73	63	$ 208	186
% Change	16.00%		12.00%
Investment Program Fees [Member]
Disaggregation of Revenue [Line Items]
Investment product fees	$ 70	70	$ 199	202
% Change	0.00%		(1.00%)
Other Investment Product Fees [Member]
Disaggregation of Revenue [Line Items]
Investment product fees	$ 8	$ 7	$ 24	$ 26
% Change	14.00%		(8.00%)

Revenue Recognition - Schedul_2

Revenue Recognition - Schedule of Contract Balances (Details) $ in Millions	9 Months Ended
	Jun. 30, 2019USD ($)
Contract With Customer, Balance [Roll Forward]
Opening balance, October 1, 2018	$ 138
Closing balance, June 30, 2019	151
Increase	13
Receivable From Clients [Member]
Contract With Customer, Balance [Roll Forward]
Opening balance, October 1, 2018	16
Closing balance, June 30, 2019	17
Increase	1
Receivable From Affiliates [Member]
Contract With Customer, Balance [Roll Forward]
Opening balance, October 1, 2018	7
Closing balance, June 30, 2019	7
Increase	0
Other Receivables [Member]
Contract With Customer, Balance [Roll Forward]
Opening balance, October 1, 2018	115
Closing balance, June 30, 2019	127
Increase	$ 12