TD Ameritrade Holding 10-K 21 Nov 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Sep. 30, 2014	Nov. 07, 2014	Mar. 31, 2014
Document And Entity Information [Abstract]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	30-Sep-14	'	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'AMTD	'	'
Entity Registrant Name	'TD AMERITRADE HOLDING CORP	'	'
Entity Central Index Key	'0001173431	'	'
Current Fiscal Year End Date	'--09-30	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Common Stock, Shares Outstanding	'	543,824,055	'
Entity Public Float	'	'	$8.70

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$1,460	$1,062
Cash and investments segregated and on deposit for regulatory purposes	5,116	5,894
Receivable from brokers, dealers and clearing organizations	1,108	1,348
Receivable from clients, net	11,639	8,984
Receivable from affiliates	99	117
Other receivables, net	147	137
Securities owned, at fair value	332	323
Property and equipment at cost, net	543	497
Goodwill	2,467	2,467
Acquired intangible assets, net	751	841
Other assets	169	166
Total assets	23,831	21,836
Liabilities:	'	'
Payable to brokers, dealers and clearing organizations	2,421	1,973
Payable to clients	14,497	13,183
Accounts payable and other liabilities	595	596
Payable to affiliates	5	4
Notes payable	150	0
Long-term debt	1,101	1,052
Deferred income taxes	314	352
Total liabilities	19,083	17,160
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; 631 million shares issued; 2014 — 545 million shares outstanding; 2013 — 550 million shares outstanding	6	6
Additional paid-in capital	1,618	1,592
Retained earnings	4,551	4,304
Treasury stock, common, at cost: 2014 — 86 million shares; 2013 — 81 million shares	-1,409	-1,226
Accumulated other comprehensive loss	-18	0
Total stockholders' equity	4,748	4,676
Total liabilities and stockholders' equity	$23,831	$21,836

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2014	Sep. 30, 2013
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	631,000,000	631,000,000
Common stock, shares outstanding	545,000,000	550,000,000
Treasury stock, shares	86,000,000	81,000,000

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Transaction-based revenues:	'	'	'
Commissions and transaction fees	$1,351	$1,171	$1,087
Asset-based revenues:	'	'	'
Interest revenue	587	476	456
Brokerage interest expense	-6	-7	-6
Net interest revenue	581	469	450
Insured deposit account fees	820	804	828
Investment product fees	309	250	196
Total asset-based revenues	1,710	1,523	1,474
Other revenues	62	70	80
Net revenues	3,123	2,764	2,641
Operating expenses:	'	'	'
Employee compensation and benefits	760	692	690
Clearing and execution costs	134	109	89
Communications	116	113	111
Occupancy and equipment costs	156	160	150
Depreciation and amortization	95	86	72
Amortization of acquired intangible assets	90	91	92
Professional services	155	145	168
Advertising	250	239	248
Other	82	73	87
Total operating expenses	1,838	1,708	1,707
Operating income	1,285	1,056	934
Other expense (income):	'	'	'
Interest on borrowings	25	25	28
Gain on investments, net	-10	-57	0
Total other expense (income)	15	-32	28
Pre-tax income	1,270	1,088	906
Provision for income taxes	483	413	320
Net income	$787	$675	$586
Earnings per share - basic (in dollars per share)	$1.43	$1.23	$1.07
Earnings per share - diluted (in dollars per share)	$1.42	$1.22	$1.06
Weighted average shares outstanding - basic (in shares)	550	549	548
Weighted average shares outstanding - diluted (in shares)	554	554	554
Dividends declared per share (in dollars per share)	$0.98	$0.86	$0.24

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]	'	'	'
Net income	$787	$675	$586
Investments available-for-sale	'	'	'
Net unrealized gain	0	21	28
Reclassification adjustment for net realized gain included in net income	0	-52	0
Reclassification of impairment charge	0	3	0
Cash flow hedging instruments	'	'	'
Net unrealized loss	-29	0	0
Total other comprehensive income (loss), before tax	-29	-28	28
Income tax effect	11	10	-10
Total other comprehensive income (loss), net of tax	-18	-18	18
Comprehensive income	$769	$657	$604

CONSOLIDATED_STATEMENTS_OF_STO

CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) Member]
In Millions, unless otherwise specified
Beginning Balance, Value at Sep. 30, 2011	$4,116	$6	$1,584	$3,646	($1,120)	$0
Beginning Balance (in shares) at Sep. 30, 2011	554	'	'	'	'	'
Shareholders Equity [Line Items]	'	'	'	'	'	'
Net income	586	'	'	586	'	'
Other comprehensive income, net of tax	18	'	'	'	'	18
Payment of cash dividends	-132	'	'	-132	'	'
Repurchases of common stock	-208	'	'	'	-208	'
Repurchases of common stock (in shares)	-12	'	'	'	'	'
Common stock issued for stock-based compensation, including tax effects	4	'	-38	'	42	'
Common stock issued for stock-based compensation, including tax effects (in shares)	3	'	'	'	'	'
Stock-based compensation expense	41	'	41	'	'	'
Ending Balance, Value at Sep. 30, 2012	4,425	6	1,587	4,100	-1,286	18
Ending Balance (in shares) at Sep. 30, 2012	545	'	'	'	'	'
Shareholders Equity [Line Items]	'	'	'	'	'	'
Net income	675	'	'	675	'	'
Other comprehensive income, net of tax	-18	'	'	'	'	-18
Payment of cash dividends	-471	'	'	-471	'	'
Repurchases of common stock	-5	'	'	'	-5	'
Common stock issued for stock-based compensation, including tax effects	41	'	-24	'	65	'
Common stock issued for stock-based compensation, including tax effects (in shares)	5	'	'	'	'	'
Stock-based compensation expense	29	'	29	'	'	'
Ending Balance, Value at Sep. 30, 2013	4,676	6	1,592	4,304	-1,226	0
Ending Balance (in shares) at Sep. 30, 2013	550	'	'	'	'	'
Shareholders Equity [Line Items]	'	'	'	'	'	'
Net income	787	'	'	787	'	'
Other comprehensive income, net of tax	-18	'	'	'	'	-18
Payment of cash dividends	-540	'	'	-540	'	'
Repurchases of common stock	-207	'	'	'	-207	'
Repurchases of common stock (in shares)	-7	'	'	'	'	'
Common stock issued for stock-based compensation, including tax effects	18	'	-6	'	24	'
Common stock issued for stock-based compensation, including tax effects (in shares)	2	'	'	'	'	'
Stock-based compensation expense	32	'	32	'	'	'
Ending Balance, Value at Sep. 30, 2014	$4,748	$6	$1,618	$4,551	($1,409)	($18)
Ending Balance (in shares) at Sep. 30, 2014	545	'	'	'	'	'

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:	'	'	'
Net income	$787	$675	$586
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation and amortization	95	86	72
Amortization of acquired intangible assets	90	91	92
Deferred income taxes	-27	10	5
Gain on investments, net	-10	-57	0
Stock-based compensation	32	29	41
Excess tax benefits on stock-based compensation	-10	-24	-9
Other, net	1	2	8
Changes in operating assets and liabilities:	'	'	'
Cash and investments segregated and on deposit for regulatory purposes	778	-1,864	-1,511
Receivable from brokers, dealers and clearing organizations	240	-238	-275
Receivable from clients, net	-2,655	-337	-588
Receivable from/payable to affiliates, net	19	-32	7
Other receivables, net	-10	-19	-3
Securities owned, at fair value	-10	20	104
Other assets	-37	4	0
Payable to brokers, dealers and clearing organizations	448	-19	282
Payable to clients	1,314	2,455	1,749
Accounts payable and accrued liabilities	-20	-43	32
Net cash provided by operating activities	1,025	739	592
Cash flows from investing activities:	'	'	'
Purchase of property and equipment	-144	-144	-186
Purchase of short-term investments	-4	-4	-155
Proceeds from sale and maturity of short-term investments	4	154	4
Proceeds from sale of investments	25	88	2
Purchase of investments	0	0	-44
Other, net	2	2	2
Net cash provided by (used in) investing activities	-117	96	-377
Cash flows from financing activities:	'	'	'
Proceeds from issuance of long-term debt	69	0	0
Principal payments on long-term debt	0	-250	0
Proceeds from notes payable	230	275	0
Principal payments on notes payable	-80	-275	0
Payment of cash dividends	-540	-471	-132
Proceeds from exercise of stock options	8	19	5
Purchase of treasury stock	-207	-5	-208
Principal payments on capital lease obligations	0	-5	-6
Excess tax benefits on stock-based compensation	10	24	9
Net cash used in financing activities	-510	-688	-332
Net increase (decrease) in cash and cash equivalents	398	147	-117
Cash and cash equivalents at beginning of year	1,062	915	1,032
Cash and cash equivalents at end of year	1,460	1,062	915
Supplemental cash flow information:	'	'	'
Interest paid	30	32	34
Income taxes paid	$489	$379	$313

Nature_of_Operations_and_Summa

Nature of Operations and Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Nature of Operations and Summary of Significant Accounting Policies	'
	Nature of Operations and Summary of Significant Accounting Policies
	Basis of Presentation — The consolidated financial statements include the accounts of TD Ameritrade Holding Corporation (the “Parent”), a Delaware corporation, and its wholly-owned subsidiaries (collectively, the “Company”). Intercompany balances and transactions have been eliminated.
	Nature of Operations — The Company provides securities brokerage services, including trade execution, clearing services and margin lending, through its broker-dealer subsidiaries. The Company provides trustee, custodial and other trust-related services to retirement plans and other custodial accounts through its state-chartered trust company subsidiary. The Company also provides cash sweep and deposit account products through third-party relationships.
	The Company’s broker-dealer subsidiaries are subject to regulation by the Securities and Exchange Commission (“SEC”), the Financial Industry Regulatory Authority (“FINRA”), the Commodity Futures Trading Commission (“CFTC”), the National Futures Association (“NFA”) and the various exchanges in which they maintain membership. Dividends from the Company’s broker-dealer and trust company subsidiaries are a source of liquidity for the holding company. Requirements of the SEC, FINRA and CFTC relating to liquidity, net capital standards and the use of client funds and securities may limit funds available for the payment of dividends from the broker-dealer subsidiaries to the holding company. State regulatory requirements may limit funds available for the payment of dividends from the trust company subsidiary to the holding company.
	Use of Estimates — The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Cash and Cash Equivalents — The Company considers temporary, highly-liquid investments with an original maturity of three months or less to be cash equivalents, except for amounts required to be segregated for regulatory purposes.
	Cash and Investments Segregated and on Deposit for Regulatory Purposes — Cash and investments segregated and on deposit for regulatory purposes consists 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. Funds can be held in cash, reverse repurchase agreements, U.S. Treasury securities and other qualified securities. Reverse repurchase agreements (securities purchased under agreements to resell) 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 are collateralized by U.S. Treasury securities and generally have a maturity of seven days. Cash and investments segregated and on deposit for regulatory purposes also includes amounts that have been segregated or secured for the benefit of futures clients according to the regulations of the CFTC governing futures commission merchants.
	Securities Borrowed and Securities Loaned — Securities borrowed and securities loaned transactions are recorded at the amount of cash collateral provided or received. Securities borrowed transactions require the Company to provide the counterparty with collateral in the form of cash. The Company receives collateral in the form of cash for securities loaned transactions. For these transactions, the fees earned or incurred by the Company are recorded as interest revenue and brokerage interest expense, respectively, on the Consolidated Statements of Income. The related interest receivable from and the brokerage interest payable to broker-dealers are included in other receivables and in accounts payable and other liabilities, respectively, on the Consolidated Balance Sheets.
	Receivable from/Payable to Clients — Receivable from clients primarily consists of margin loans to securities brokerage clients, which are collateralized by client securities, and is carried at the amount receivable, net of an allowance for doubtful accounts that is primarily based on the amount of unsecured margin balances. Payable to clients primarily consists of client cash held in brokerage accounts and is carried at the amount of client cash on deposit. The Company earns interest revenue and pays interest expense on its receivable from client and payable to client balances, respectively. The interest revenue and expense are included in net interest revenue on the Consolidated Statements of Income.
	Securities Owned — Securities owned by our broker-dealer subsidiaries are recorded on a trade-date basis and carried at fair value, and the related changes in fair value are generally included in other revenues on the Consolidated Statements of Income.
	Property and Equipment — Property and equipment is recorded at cost, net of accumulated depreciation and amortization, except for land, which is recorded at cost. Depreciation is provided using the straight-line method over the estimated useful service lives of the assets, which range from 10 to 40 years for buildings and building components and three to seven years for all other depreciable property and equipment. Leasehold improvements are amortized over the lesser of the economic useful life of the improvement or the term of the lease.
	Software Development — From the date technological feasibility has been established until beta testing is complete, software development costs are capitalized and included in property and equipment. Once the product is fully functional, such costs are amortized in accordance with the Company’s normal accounting policies. Software development costs that do not meet capitalization criteria are expensed as incurred.
	Goodwill — The Company has recorded goodwill for purchase business combinations to the extent the purchase price of each completed acquisition exceeded the fair value of the net identifiable assets of the acquired company. The Company tests goodwill for impairment on at least an annual basis. In performing the impairment tests, the Company utilizes quoted market prices of the Company’s common stock to estimate the fair value of the Company as a whole. The estimated fair value is then allocated to the Company’s reporting units, if applicable, based on operating revenues, and is compared with the carrying value of the reporting units. No impairment charges have resulted from the annual impairment tests.
	Amortization of Acquired Intangible Assets — Acquired intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives, ranging from three to 23 years. The acquired intangible asset associated with a trademark license agreement is not subject to amortization because the term of the agreement is considered to be indefinite.
	Long-Lived Assets and Acquired Intangible Assets — The Company reviews its long-lived assets and finite-lived acquired intangible assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The Company evaluates recoverability by comparing the undiscounted cash flows associated with the asset to the asset’s carrying amount. The Company also evaluates the remaining useful lives of intangible assets to determine if events or trends warrant a revision to the remaining period of amortization.
	The Company tests its indefinite-lived acquired intangible asset for impairment on at least an annual basis. To determine if the indefinite-lived intangible asset is impaired, the Company first assesses certain qualitative factors. Based on this assessment, if it is determined that more likely than not the fair value of the indefinite-lived intangible asset is less than its carrying amount, the Company performs a quantitative impairment test. No impairment charges have resulted from the annual impairment tests.
	Income Taxes — The Company files a consolidated U.S. income tax return with its subsidiaries on a calendar year basis, combined returns for state tax purposes where required and certain of its subsidiaries file separate state income tax returns where required. Deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates expected to apply to taxable income in the periods in which the deferred tax asset or liability is expected to be settled or realized. Uncertain tax positions are recognized if they are more likely than not to be sustained upon examination, based on the technical merits of the position. The amount of tax benefit recognized is the largest amount of benefit that is greater than 50% likely of being realized upon settlement. The Company recognizes interest and penalties, if any, related to income tax matters as part of the provision for income taxes on the Consolidated Statements of Income.
	Capital Stock — The authorized capital stock of the Company consists of a single class of common stock and one or more series of preferred stock as may be authorized for issuance by the Company’s board of directors. Voting, dividend, conversion and liquidation rights of the preferred stock would be established by the board of directors upon issuance of such preferred stock.
	Stock-Based Compensation — The Company measures and recognizes compensation expense based on estimated grant date fair values for all stock-based payment arrangements. Stock-based compensation expense is based on awards expected to vest and therefore is reduced for estimated forfeitures. Forfeitures are estimated at the time of grant based on the Company’s historical forfeiture experience and revised in subsequent periods if actual forfeitures differ from those estimates.
	Transaction-based Revenues — Client securities trades are recorded on a settlement-date basis with such trades generally settling within three business days after the trade date. Revenues and expenses related to client trades, including order routing revenue (also referred to as payment for order flow) and revenues from markups on riskless principal trades in fixed-income securities, are recorded on a trade-date basis. Revenues related to client trades are recorded net of promotional allowances. Securities owned by clients, including those that collateralize margin or similar transactions, are not reflected in the accompanying consolidated financial statements.
	Net Interest Revenue — Net interest revenue primarily consists of income generated by client cash and interest charged to clients on margin balances, net of interest paid to clients on their credit balances. It also includes net interest revenue from securities borrowed and securities loaned transactions.
	Insured Deposit Account Fees — Insured deposit account fees consist of revenues resulting from the Insured Deposit Account (“IDA”) agreement with TD Bank USA, N.A. (“TD Bank USA”), TD Bank, N.A. and The Toronto-Dominion Bank (“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 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 IDA agreement is described further in Note 18.
	Investment Product Fees — Investment product fee revenue consists of revenues earned on client assets invested in money market mutual funds, other mutual funds and certain Company-sponsored investment programs.
	Advertising — The Company expenses advertising costs the first time the advertising takes place.
	Derivatives and Hedging Activities — The Company occasionally utilizes derivative instruments to manage risks, which may include market price, interest rate and foreign currency risks. The Company does not use derivative instruments for speculative or trading purposes. Derivatives are recorded on the Consolidated Balance Sheets as assets or liabilities at fair value. Derivative instruments properly designated to hedge exposure to changes in the fair value of assets or liabilities are accounted for as fair value hedges. Derivative instruments properly designated to hedge exposure to the variability of expected future cash flows or other forecasted transactions are accounted for as cash flow hedges. The Company formally documents the risk management objective and strategy for each hedge transaction. Derivative instruments that do not qualify for hedge accounting are carried at fair value on the Consolidated Balance Sheets with unrealized gains and losses recorded currently on the Consolidated Statements of Income. Cash flows from derivative instruments accounted for as fair value hedges or cash flow hedges are classified in the same category on the Consolidated Statements of Cash Flows as the cash flows from the items being hedged. For additional information on the Company's fair value and cash flow hedging instruments, see Note 8.
	Earnings Per Share — Basic earnings per share (“EPS”) is computed by dividing net income by the weighted average common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock, except when such assumed exercise or conversion would have an antidilutive effect on EPS. The difference between the numerator and denominator used in the Company's computation of basic and diluted earnings per share consists of common stock equivalent shares related to stock-based compensation. The Company excluded from the calculation of diluted earnings per share 0.7 million and 2.5 million shares underlying the stock-based compensation awards for fiscal years 2013 and 2012, respectively, because their inclusion would have been antidilutive. There were no material antidilutive awards for fiscal year 2014.
	Recently Adopted Accounting Pronouncements
	ASU 2011-11 — On October 1, 2013 the Company retrospectively adopted, for all comparative periods presented, Accounting Standards Update (“ASU”) 2011-11, Disclosures about Offsetting Assets and Liabilities, and ASU 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities. The amendments in these ASUs enhance disclosures by requiring additional information about financial and derivative instruments, including bifurcated embedded derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing and securities lending transactions that are either (1) offset (netting assets and liabilities) in accordance with Section 210-20-45 or Section 815-10-45 of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification (“ASC”) or (2) subject to an enforceable master netting arrangement or similar agreement. Adoption of ASU 2011-11 and ASU 2013-01 resulted only in the additional disclosures presented in Note 15.
	Recently Issued Accounting Pronouncements
	ASU 2014-09 — In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, 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 will supersede 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. An entity may apply the amendments in ASU 2014-09 by using one of the following two methods: (1) retrospective application to each prior reporting period presented or (2) a modified retrospective approach, requiring 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. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. Therefore, ASU 2014-09 will be effective for the Company's fiscal year beginning October 1, 2017. Early adoption is not permitted. The Company is currently assessing the impact that ASU 2014-09 will have on the Company's financial statements and evaluating which adoption method to apply.
	ASU 2014-11 — In June 2014, the FASB issued ASU 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. The amendments in ASU 2014-11 will require entities to account for repurchase-to-maturity transactions and linked repurchase financings as secured borrowings, which is consistent with the accounting for other repurchase agreements. The amendments also require new disclosures, including information regarding collateral pledged in securities lending transactions and similar transactions that are accounted for as secured borrowings. The accounting changes in ASU 2014-11 are effective for the first interim or annual period beginning after December 15, 2014, and the new disclosures related to collateral pledged in transactions that are accounted for as secured borrowings are required to be presented for annual periods beginning after December 15, 2014 and for interim periods beginning after March 15, 2015. Because the Company does not act as a transferor in repurchase-to-maturity transactions or linked repurchase financings, the Company's adoption of ASU 2014-11 is not expected to result in any accounting changes. The new disclosure requirements of ASU 2014-11 will be effective for the Company's fiscal quarter beginning April 1, 2015.

Cash_and_Cash_Equivalents

Cash and Cash Equivalents	12 Months Ended
	Sep. 30, 2014
Cash and Cash Equivalents [Abstract]	'
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	The Company’s cash and cash equivalents is summarized in the following table (dollars in millions):
		September 30,
		2014		2013
	Corporate	$	298	$	429
	Broker-dealer subsidiaries	1,090		540
	Trust company subsidiary	53		74
	Investment advisory subsidiaries	19		19
	Total	$	1,460	$	1,062
	Capital requirements may limit the amount of cash available for dividend from the broker-dealer and trust company subsidiaries to the parent company. Most of the trust company cash and cash equivalents arises from client transactions in the process of settlement, and therefore is generally not available for corporate purposes. Cash and cash equivalents of the investment advisory subsidiaries is generally not available for corporate purposes.

Cash_and_Investments_Segregate

Cash and Investments Segregated and on Deposit for Regulatory Purposes	12 Months Ended
	Sep. 30, 2014
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):
		September 30,
		2014		2013
	U.S. government debt securities	$	3,070	$	1,995
	Reverse repurchase agreements (collateralized by U.S. government debt securities)	1,193		2,618
	Cash in demand deposit accounts	617		1,154
	Cash on deposit with futures commission merchants	186		77
	U.S. government debt securities on deposit with futures commission merchant	50		50
	Total	$	5,116	$	5,894

Receivable_from_and_Payable_to

Receivable from and Payable to Brokers, Dealers and Clearing Organizations	12 Months Ended
	Sep. 30, 2014
Brokers and Dealers [Abstract]	'
Receivable from and Payable to Brokers, Dealers and Clearing Organizations	'
	Receivable from and Payable to Brokers, Dealers and Clearing Organizations
	Amounts receivable from and payable to brokers, dealers and clearing organizations consist of the following (dollars in millions):
		September 30,
		2014		2013
	Receivable:
	Deposits paid for securities borrowed	$	995	$	1,220
	Broker-dealers	3		9
	Clearing organizations	104		115
	Securities failed to deliver	6		4
	Total	$	1,108	$	1,348
	Payable:
	Deposits received for securities loaned	$	2,384	$	1,948
	Broker-dealers	3		2
	Clearing organizations	23		15
	Securities failed to receive	11		8
	Total	$	2,421	$	1,973

Allowance_for_Doubtful_Account

Allowance for Doubtful Accounts on Receivables	12 Months Ended
	Sep. 30, 2014
Valuation and Qualifying Accounts [Abstract]	'
Allowance for Doubtful Accounts on Receivables	'
	Allowance for Doubtful Accounts on Receivables
	The following table summarizes activity in the Company’s allowance for doubtful accounts on client and other receivables for the fiscal years indicated (dollars in millions):
		2014			2013			2012
	Beginning balance	$	15		$	21		$	18
	Provision for (recovery of) doubtful accounts, net	3			(1		)	9
	Write-off of doubtful accounts	(8		)	(5		)	(6		)
	Ending balance	$	10		$	15		$	21

Property_and_Equipment

Property and Equipment	12 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Property and Equipment	'
	Property and Equipment
	Property and equipment consists of the following (dollars in millions):
		September 30,
		2014			2013
	Buildings and building components	$	264		$	198
	Computer equipment	220			205
	Software	170			144
	Leasehold improvements	156			148
	Land	20			17
	Other property and equipment	72			67
		902			779
	Less: Accumulated depreciation and amortization	(359		)	(282		)
	Property and equipment, net	$	543		$	497

Goodwill_and_Acquired_Intangib

Goodwill and Acquired Intangible Assets	12 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Acquired Intangible Assets	'
	Goodwill and Acquired Intangible Assets
	The Company has recorded goodwill for purchase business combinations to the extent the purchase price of each completed acquisition exceeded the fair value of the net identifiable tangible and intangible assets of each acquired company. There were no material changes in the carrying amount of goodwill during the fiscal years ended September 30, 2014 and 2013.
	Acquired intangible assets consist of the following (dollars in millions):
		September 30,
		2014							2013
		Gross		Accumulated			Net		Gross		Accumulated			Net
		Carrying		Amortization			Carrying		Carrying		Amortization			Carrying
		Amount					Amount		Amount					Amount
	Client relationships	$	1,228	$	(645	)	$	583	$	1,228	$	(569	)	$	659
	Technology and content	99		(77		)	22		99		(63		)	36
	Trademark license	146		—			146		146		—			146
		$	1,473	$	(722	)	$	751	$	1,473	$	(632	)	$	841
	Amortization expense on acquired intangible assets was $90 million, $91 million and $92 million for fiscal years 2014, 2013 and 2012, respectively. Estimated future amortization expense for acquired intangible assets outstanding as of September 30, 2014 is as follows (dollars in millions):
	Fiscal Year	Estimated
		Amortization
		Expense
	2015	$	90
	2016	85
	2017	76
	2018	72
	2019	68
	Thereafter (to 2025)	214
	Total	$	605

Notes_Payable_and_Longterm_Deb

Notes Payable and Long-term Debt	12 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Notes Payable and Long-term Debt	'
	Notes Payable and Long-term Debt
	Notes payable and long-term debt consist of the following (dollars in millions):
	30-Sep-14	Face				Fair Value				Net Carrying
		Value				Adjustment(1)				Value
	Notes payable:
	Parent Revolving Facility	$	150			$	—			$	150
	Long-term debt:
	Senior Notes:
	4.150% Notes due 2014	500				2				502
	5.600% Notes due 2019	500				30				530
	Secured Loan:
	Variable-rate Note due 2019	69				—				69
	Subtotal - Long-term debt	1,069				32				1,101
	Total notes payable and long-term debt	$	1,219			$	32			$	1,251
	30-Sep-13	Face				Fair Value				Net Carrying
		Value				Adjustment(1)				Value
	Senior Notes:
	4.150% Notes due 2014	$	500			$	15			$	515
	5.600% Notes due 2019	500				37				537
	Total long-term debt	$	1,000			$	52			$	1,052
	(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 September 30, 2014 are as follows (dollars in millions):
	2015	$	510
	2016	14
	2017	14
	2018	14
	2019	14
	Thereafter	503
	Total	$	1,069
	Senior Notes — As of September 30, 2014 and 2013, the Company had $500 million aggregate principal amount of 4.150% Senior Notes due December 1, 2014 (the “2014 Notes”) and $500 million aggregate principal amount of 5.600% Senior Notes due December 1, 2019 (the “2019 Notes”). The 2014 Notes and 2019 Notes are unsecured and were sold on November 25, 2009 through a public offering. Interest on the 2014 Notes and 2019 Notes is payable semi-annually in arrears on June 1 and December 1 of each year.
	The 2014 Notes and 2019 Notes are jointly and severally and fully and unconditionally guaranteed by each of the Company’s current and future subsidiaries that is or becomes a borrower or a guarantor under the TD Ameritrade Holding Corporation Credit Agreement, dated as of June 11, 2014, as described below. Currently, the only subsidiary guarantor of the obligations under the 2014 Notes and 2019 Notes is TD Ameritrade Online Holdings Corp. (“TDAOH”). The 2014 Notes, 2019 Notes and the guarantee by TDAOH are the general senior unsecured obligations of the Company and TDAOH.
	The Company may redeem the 2014 Notes and 2019 Notes, in whole at any time or in part from time to time, 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: 30 basis points in the case of the 2014 Notes and 35 basis points in the case of the 2019 Notes, plus, in each case, accrued and unpaid interest to the date of redemption.
	On October 17, 2014, the Company sold, through a public offering, $500 million aggregate principal amount of unsecured 3.625% Senior Notes due April 1, 2025 (the “2025 Notes”). Interest on the 2025 Notes will be payable in arrears semi-annually on April 1 and October 1 of each year. The Company intends to use the net proceeds from the issuance of the 2025 Notes, together with cash on hand, to repay in full the outstanding principal under the Company's 2014 Notes that mature on December 1, 2014.
	The Company's obligations in respect to the 2025 Notes are not guaranteed by any of its subsidiaries. The Company may redeem the 2025 Notes, in whole or in part, at any time prior to January 1, 2025 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 25 basis points, plus accrued and unpaid interest to the date of redemption. The Company may redeem the 2025 Notes, in whole or in part, at any time on or after January 1, 2025 at a redemption price equal to 100% of the principal amount of the notes being redeemed, plus accrued and unpaid interest to the date of redemption.
	Secured Loan — On September 15, 2014, the Company entered into a bank loan agreement (the “Loan Agreement”) in the aggregate principal amount of $69 million, the proceeds of which were used to purchase real estate for use in the Company’s operations. The loan is secured by a lien against the purchased real estate and is guaranteed by TDAOH and ThinkTech, Inc., a subsidiary of the Company. The principal amount of the loan plus accrued interest is due and payable in 20 consecutive quarterly installments, beginning January 1, 2015, with the last installment due on October 1, 2019. The interest rate under the Loan Agreement is based on the one-month London Interbank Offered Rate (“LIBOR”), adjusted and determined monthly, plus 1.375 percentage points. At September 30, 2014, the interest rate was 1.53%. The Company may prepay any principal or interest under the loan without penalty or other cost. The covenants applicable under the Loan Agreement are substantially consistent with the terms of the TD Ameritrade Holding Corporation Credit Agreement, dated June 11, 2014, described below.
	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 this exposure, on December 30, 2009, the Company entered into a fixed-for-variable interest rate swap on the 2014 Notes for a notional amount of $500 million, with a maturity date matching the maturity date of the 2014 Notes. In addition, on January 7, 2011, the Company entered into a fixed-for-variable interest rate swap on the 2019 Notes for a notional amount of $500 million, with a maturity date matching the maturity date of the 2019 Notes. The interest rate swaps effectively change the fixed-rate interest on the 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 Senior Notes, and makes quarterly variable-rate interest payments based on three-month LIBOR plus (a) 1.245% for the swap on the 2014 Notes and (b) 2.3745% for the swap on the 2019 Notes. As of September 30, 2014, the weighted average effective interest rate on the Senior Notes was 2.04%.
	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 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 fiscal years indicated (dollars in millions):
		2014				2013				2012
	Gain (loss) on fair value of interest rate swaps	$	(20	)		$	(44	)		$	8
	Gain (loss) on fair value of hedged fixed-rate debt	20				44				(8		)
	Net gain (loss) recorded in interest on borrowings	$	—			$	—			$	—
	In addition, on November 19, 2014, the Company entered into a fixed-for-variable interest rate swap on the 2025 Notes for a notional amount of $500 million, with a maturity date matching the maturity date of the 2025 Notes. Under the terms of this interest rate swap agreement, the Company receives semi-annual fixed-rate interest payments based on the same rate applicable to the 2025 Notes, and makes quarterly variable-rate interest payments based on three-month LIBOR plus 1.1022%.
	Cash Flow Hedging – On January 17, 2014, the Company entered into forward-starting interest rate swap contracts with an aggregate notional amount of $500 million, to hedge against changes in the benchmark interest rate component of future interest payments resulting from the anticipated refinancing of the 2014 Notes.  The Company designated the contracts as a cash flow hedge of the future interest payments.
	Under cash flow hedge accounting, until settlement the swap contracts are carried at fair value and, to the extent they are an effective hedge, any unrealized gains or losses are recorded in other comprehensive income (loss). Any ineffective portion of the unrealized gains or losses is immediately recorded into earnings. Upon settlement, any realized gain or loss that has been recorded in other comprehensive income (loss) is amortized into earnings over the term of the newly-issued fixed-rate debt. The Company evaluates the effectiveness of forward-starting interest rate swap agreements on a quarterly basis. The Company did not record any ineffectiveness for the fiscal year ended September 30, 2014.
	On October 17, 2014, the Company sold $500 million of 2025 Notes as described under “Senior Notes” above, and paid approximately $45 million to settle the forward-starting interest rate swap contracts. As of October 17, 2014, the Company recorded $0.5 million of pre-tax loss immediately into earnings to reflect ineffectiveness resulting from the issuance of the 2025 Notes slightly earlier than forecast, and expects to reclassify another $4.4 million of pre-tax net unrealized losses, that were reported in accumulated other comprehensive income (loss), into earnings within the next 12 months.
	The following table summarizes pre-tax losses resulting from changes in the fair value of the forward-starting interest rate swaps for the fiscal years indicated (dollars in millions):
		Amount of Loss Recognized in
		Other Comprehensive Income (Loss)
		(Effective Portion)
		2014				2013				2012
	Forward-starting interest rate swaps	$	(29	)		$	—			$	—
	Balance Sheet Impact of Hedging Instruments — The following table summarizes the fair value of outstanding derivatives designated as hedging instruments on the Consolidated Balance Sheets (dollars in millions):
		Balance Sheet Location		September 30,
				2014				2013
	Interest rate contracts:
	Pay-variable interest rate swaps designated as fair value hedges	Other assets		$	32			$	52
	Forward-starting interest rate swaps designated as cash flow hedges	Accounts payable and other liabilities		$	(29	)		$	—
	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 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 September 30, 2014 and 2013, the pay-variable interest rate swap counterparties had pledged $47 million and $67 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 Consolidated Balance Sheets. As of September 30, 2014 the Company had pledged $43 million of collateral to the forward-starting 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 assets on the Consolidated Balance Sheets.
	TD Ameritrade Holding Corporation Credit Agreement — On June 11, 2014, the Parent entered into a credit agreement consisting of a senior unsecured revolving credit facility in the aggregate principal amount of $300 million (the “Parent Revolving Facility”). The Parent Revolving Facility replaced the Parent's prior $300 million unsecured revolving credit facility, which was scheduled to expire on June 28, 2014. The maturity date of the Parent Revolving Facility is June 11, 2019.
	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 LIBOR loans”) or (b) (i) the highest of (x) the prime rate, (y) the federal funds effective rate plus 0.50% or (z) one-month LIBOR plus 1.00%, plus (ii) an interest rate margin (“Base Rate loans”). The interest rate margin ranges from 0.875% to 1.75% for Parent LIBOR loans and from 0% to 0.75% for Base Rate loans, determined by reference to the Company’s public debt ratings. The Parent is obligated to pay a commitment fee ranging from 0.10% to 0.25% on any unused amount of the Parent Revolving Facility, determined by reference to the Company's public debt ratings.
	As of September 30, 2014, there was $150 million of borrowings outstanding under the Parent Revolving Facility, consisting of Parent LIBOR loans. There were no borrowings outstanding under the Parent's prior unsecured revolving credit facility as of September 30, 2013. As of September 30, 2014, the commitment fee was 0.15% and the interest rate margin was 1.25%, each determined by reference to the Company’s public debt ratings, and the interest rate was 1.40%, based on one-month LIBOR plus the interest rate margin.
	The obligations under the Parent Revolving Facility are guaranteed by TDAOH and each “significant subsidiary” (as defined in SEC Rule 1-02(w) of Regulation S-X) of the Parent, other than broker-dealer subsidiaries, futures commission merchant subsidiaries and controlled foreign corporations. Currently, the only subsidiary guarantor of the obligations under the Parent Revolving Facility is TDAOH.
	The Parent Revolving Facility contains negative covenants that limit or restrict, subject to certain exceptions, the incurrence of liens, indebtedness of subsidiaries, mergers, consolidations, transactions with affiliates, change in nature of business and the sale of all or substantially all of the assets of the Company. The Parent is also required to maintain compliance with a maximum consolidated leverage ratio covenant and a minimum consolidated interest coverage ratio covenant, and the Company's broker-dealer subsidiaries are required to maintain compliance with a minimum regulatory net capital covenant. The Company was in compliance with all covenants under the Parent Revolving Facility as of September 30, 2014.
TD Ameritrade Clearing, Inc. Credit Agreement - On June 11, 2014, TD Ameritrade Clearing, Inc. (“TDAC”), the Company’s clearing broker-dealer subsidiary, entered into a credit agreement consisting of a senior unsecured revolving credit facility in the aggregate principal amount of $300 million (the “TDAC Revolving Facility”). The TDAC Revolving Facility replaced TDAC’s prior $300 million unsecured revolving credit facility, which was scheduled to expire on June 28, 2014. The maturity date of the TDAC Revolving Facility is June 11, 2019.
The applicable interest rate under the TDAC Revolving Facility is calculated as a per annum rate equal to, at the option of TDAC, (a) LIBOR plus an interest rate margin (“TDAC LIBOR loans”) or (b) the federal funds effective rate plus an interest rate margin (“Fed Funds Rate loans”). The interest rate margin ranges from 0.75% to 1.50% for both TDAC LIBOR loans and Fed Funds Rate loans, determined by reference to the Company’s public debt ratings. TDAC is obligated to pay a commitment fee ranging from 0.08% to 0.20% on any unused amount of the TDAC Revolving Facility, determined by reference to the Company’s public debt ratings. As of September 30, 2014, the interest rate margin would have been 1.00% for both TDAC LIBOR loans and Fed Funds Rate loans, and the commitment fee was 0.125%, each determined by reference to the Company’s public debt ratings. There were no borrowings outstanding under the TDAC Revolving Facility and the prior TDAC unsecured revolving credit facility as of September 30, 2014 and 2013, respectively.
The TDAC Revolving Facility contains negative covenants that limit or restrict, subject to certain exceptions, the incurrence of liens, indebtedness of TDAC, mergers, consolidations, change in nature of business and the sale of all or substantially all of the assets of TDAC. TDAC is also required to maintain minimum tangible net worth and is required to maintain compliance with minimum regulatory net capital requirements. TDAC was in compliance with all covenants under the TDAC Revolving Facility as of September 30, 2014.

Income_Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	Provision for income taxes is comprised of the following for the fiscal years indicated (dollars in millions):
		2014				2013				2012
	Current expense:
	Federal	$	457			$	370			$	314
	State	53				33				1
		510				403				315
	Deferred expense (benefit):
	Federal	(28		)		(2		)		(2		)
	State	1				12				7
		(27		)		10				5
	Provision for income taxes	$	483			$	413			$	320
	A reconciliation of the federal statutory tax rate to the effective tax rate applicable to pre-tax income follows for the fiscal years indicated:
		2014			2013			2012
	Federal statutory rate	35	%		35	%		35	%
	State taxes, net of federal tax effect	3.1			2.6			2.1
	Adjustments to estimated state income taxes	0.2			0.4			0.1
	Interest recorded on unrecognized tax benefits, net	0.2			0.3			0.1
	Reversal of accruals for unrecognized tax benefits	(0.5	)		(0.3	)		(1.7	)
	Reversal of capital loss valuation allowance	—			—			(0.4	)
	Other	—			—			0.1
		38	%		38	%		35.3	%
	The Company’s effective income tax rate for fiscal years 2014 and 2013 was 38.0%, compared to 35.3% for fiscal year 2012. The provision for income taxes for fiscal year 2014 included $10 million of favorable resolutions of state income tax matters, partially offset by $2 million of unfavorable deferred income tax adjustments resulting from state income tax law changes. These items had a net favorable impact on the Company's earnings for fiscal year 2014 of approximately one cent per share. The provision for income taxes for fiscal year 2013 included $6 million of favorable resolutions of state income tax matters, which was mostly offset by $4 million of unfavorable deferred income tax adjustments resulting from state income tax law changes. The provision for income taxes for fiscal year 2012 was significantly lower than normal primarily due to $19 million of favorable resolutions of state income tax matters and a $3 million benefit resulting from the reversal of a valuation allowance related to a capital loss carryover. These items favorably impacted the Company’s earnings for fiscal year 2012 by approximately four cents per share.
	Deferred tax assets (liabilities) are comprised of the following (dollars in millions):
		September 30,
		2014				2013
	Deferred tax assets:
	Accrued and other liabilities	$	78			$	72
	Intangible assets, state tax benefit	10				12
	Stock-based compensation	37				36
	Allowance for doubtful accounts	5				6
	Operating loss carryforwards	12				21
	Unrealized loss on cash flow hedging instruments	11				—
	Other deferred tax assets	—				3
	Gross deferred tax assets	153				150
	Less: Valuation allowance	(9		)		(18		)
	Net deferred tax assets	144				132
	Deferred tax liabilities:
	Property and intangible assets	(452		)		(478		)
	Other deferred tax liabilities	(6		)		(5		)
	Total deferred tax liabilities	(458		)		(483		)
	Net deferred tax liabilities	$	(314	)		$	(351	)
	Included in deferred tax assets above as of September 30, 2014 and 2013, is approximately $1 million of deferred tax benefits relating to intangible asset amortization deductions expected to be claimed in various state taxing jurisdictions, which may not be offset by deferred tax liabilities arising from different taxing jurisdictions on the Consolidated Balance Sheets. These amounts are included in other assets on the Consolidated Balance Sheets.
	As of September 30, 2014, the Company has recorded a tax benefit for approximately $3 million of federal net operating loss carryover that was acquired as part of the thinkorswim Group Inc. acquisition in fiscal 2009. The net operating loss expires in 2019, and is subject to substantial annual limitations on the utilization of the net operating loss. The amount of tax benefit recorded in the financial statements represents the amount that is more likely than not to be realized within the carryforward period. At September 30, 2014, subsidiaries of the Company have approximately $173 million of separate state operating loss carryforwards. These carryforwards expire between fiscal 2015 and 2033. Because the realization of the tax benefit from state loss carryforwards is dependent on certain subsidiaries generating sufficient state taxable income in future periods, as well as annual limitations on future utilization, the Company has provided a valuation allowance against the computed benefit in order to reflect the tax benefit expected to be realized. The $9 million decrease in the valuation allowance from September 30, 2013 to September 30, 2014 was primarily due to expiration of certain state net operating loss carryforwards during fiscal 2014.
	A reconciliation of the activity related to unrecognized tax benefits follows for the fiscal years indicated (dollars in millions):
		2014				2013				2012
	Beginning balance	$	137			$	139			$	145
	Additions based on tax positions related to the current year	29				8				10
	Additions for tax positions of prior years	10				2				8
	Reductions for tax positions of prior years	(1		)		(5		)		(3		)
	Reductions due to settlements with taxing authorities	—				(1		)		(5		)
	Reductions due to lapsed statute of limitations	(10		)		(6		)		(16		)
	Ending balance	$	165			$	137			$	139
	The balance of unrecognized tax benefits as of September 30, 2014 was $165 million ($107 million net of the federal benefit on state matters), all of which, if recognized, would favorably affect the effective income tax rate in any future periods. The balance of unrecognized tax benefits as of September 30, 2013 was $137 million ($89 million net of the federal benefit on state matters), all of which, if recognized, would favorably affect the effective income tax rate in any future periods. The Company’s income tax returns are subject to review and examination by federal, state and local taxing authorities. The federal returns for 2011 through 2013 remain open under the statute of limitations. The years open to examination by state and local government authorities vary by jurisdiction, but the statute of limitations is generally three to four years from the date the tax return is filed. It is reasonably possible that the gross unrecognized tax benefits as of September 30, 2014 could decrease by up to $49 million ($32 million net of the federal benefit on state matters) within the next twelve months as a result of settlements of certain examinations or expiration of the statute of limitations with respect to other tax filings.
	The Company recognized interest and penalties expense (net of the federal benefit) of $3 million and $2 million for fiscal years 2014 and 2013, respectively. The Company recognized $3 million of net benefits for interest and penalties (net of the federal income tax effect) on the Consolidated Statement of Income for fiscal year 2012, due to the favorable resolution of an uncertain tax position. As of September 30, 2014 and 2013, accrued interest and penalties related to unrecognized tax benefits was $53 million and $48 million, respectively.

Capital_Requirements

Capital Requirements	12 Months Ended
	Sep. 30, 2014
Regulatory Capital Requirements [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 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., the Company’s introducing broker-dealer subsidiary, 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.
	Under Rule 15c3-1, TD Ameritrade, Inc. is required to maintain minimum net capital of the greater of $250,000 or 2% of aggregate debit balances. As a futures commission merchant registered with the CFTC, TD Ameritrade, Inc. is also subject to CFTC Regulation 1.17 under the Commodity Exchange Act, administered by the CFTC and the NFA, which requires the maintenance of minimum net capital of the greatest of (a) $1.0 million, (b) its futures risk-based capital requirement, equal to 8% of the total risk margin requirement for all futures positions carried by the futures commission merchant in client and nonclient accounts, or (c) its Rule 15c3-1 net capital requirement.
	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 a net capital amount of (a) less than 5% of aggregate debit balances, (b) less than 110% of its risk-based capital requirement under CFTC Regulation 1.17, or (c) less than 120% of its minimum dollar requirement. These net capital thresholds, which are specified in Exchange Act Rule 17a-11 and CFTC Regulation 1.12, are typically referred to as “early warning” net capital thresholds.
	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		Required		Net Capital		Net Capital in		Ratio of Net
		Capital		Net Capital		in Excess of		Excess of		Capital to
				(2% of		Required		Early Warning		Aggregate
				Aggregate		Net Capital		Threshold (5%		Debit Balances
				Debit Balances)				of Aggregate
								Debit Balances)
	September 30, 2014	$	1,569	$	280	$	1,289	$	868	11.19	%
	September 30, 2013	$	1,302	$	222	$	1,080	$	746	11.7	%
	TD Ameritrade, Inc.
	Date	Net		Required		Net Capital		Net Capital in
		Capital		Net Capital		in Excess of		Excess of
				(8% of Total		Required		Early Warning
				Risk Margin)		Net Capital		Threshold
								(110% of
								Required
								Net Capital)
	September 30, 2014	$	347	$	17	$	330	$	328
	September 30, 2013	$	305	$	10	$	295	$	294
	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, as defined. TDATC’s Tier 1 capital was $27 million and $23 million as of September 30, 2014 and 2013, respectively, which exceeded the required Tier 1 capital by $12 million and $8 million, respectively.

Stockbased_Compensation

Stock-based Compensation	12 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-based Compensation	'
	Stock-based Compensation
	The Company has two stock incentive plans under which Company stock-based awards may be granted: the TD Ameritrade Holding Corporation Long-Term Incentive Plan (the “LTIP”) and the 2006 Directors Incentive Plan (the “Directors Plan”). The Company also assumed stock incentive plans in connection with past business combinations. New stock awards can no longer be granted under the assumed plans.The LTIP authorizes the award of options to purchase common stock, common stock appreciation rights, restricted stock, restricted stock units, performance shares and performance units. Under the LTIP, 42,104,174 shares of the Company’s common stock are reserved for issuance to eligible employees, consultants and non-employee directors. The Directors Plan authorizes the award of options to purchase common stock, common stock appreciation rights, restricted stock units and restricted stock. Under the Directors Plan, 1,830,793 shares of the Company’s common stock are reserved for issuance to non-employee directors.
	Stock options, except for replacement options granted in connection with business combinations, are granted by the Company with an exercise price not less than the fair market value of the Company’s common stock on the grant date. Stock options generally vest over a one- to four-year period and expire 10 years after the grant date. Restricted Stock Units (“RSUs”) are awards that entitle the holder to receive shares of Company common stock following a vesting period. RSUs granted to employees generally vest after the completion of a three-year period. RSUs granted to non-employee directors generally vest over a one-year period.
	Stock-based compensation expense was $32 million, $29 million and $41 million for fiscal years 2014, 2013 and 2012, respectively. The related income tax benefits were $12 million, $11 million and $15 million for fiscal years 2014, 2013 and 2012, respectively.
	The following is a summary of option activity in the Company’s stock incentive plans for the fiscal year ended September 30, 2014:
		Number of		Weighted		Weighted	Aggregate
		Options		Average		Average	Intrinsic
		(in thousands)		Exercise		Remaining	Value
				Price		Contractual	(in millions)
						Term (Years)
	Outstanding at beginning of year	2,543		$	18.36
	Exercised	(407	)	$	17.98
	Outstanding at end of year	2,136		$	18.43	4	$	32
	Exercisable at end of year	2,136		$	18.43	4	$	32
	The Company measures the fair value of stock options using a Black-Scholes valuation model as of the date of grant. No options were granted during fiscal years 2014, 2013 and 2012. The total intrinsic value of options exercised during fiscal years 2014, 2013 and 2012 was $6 million, $65 million and $21 million, respectively. As of September 30, 2014, there was no unrecognized compensation cost related to nonvested stock option awards.
	The Company measures the fair value of RSUs based upon the volume-weighted average market price of the underlying common stock as of the date of grant. RSUs are amortized over their applicable vesting period using the straight-line method, reduced by expected forfeitures.
	The following is a summary of RSU activity in the Company’s stock incentive plans for the fiscal year ended September 30, 2014:
		Number of		Weighted
		Units		Average
		(in thousands)		Grant Date
				Fair Value
	Nonvested at beginning of year	5,351		$	17
	Granted	1,197		$	29.97
	Dividend equivalents	168		$	18.66
	Vested	(1,640	)	$	18.72
	Forfeited	(244	)	$	19.34
	Nonvested at end of year	4,832		$	19.57
	As of September 30, 2014, there was $27 million of estimated unrecognized compensation cost related to nonvested RSUs, which was expected to be recognized over a weighted average period of 1.8 years.
	Although the Company does not have a formal policy regarding issuance of shares for stock-based compensation, such shares are generally issued from treasury stock. The Stockholders Agreement entered into in connection with the acquisition of TD Waterhouse requires the Company to repurchase its common stock from time to time to offset dilution resulting from stock option exercises and other stock awards subsequent to the acquisition. As of September 30, 2014, the Company was not obligated to repurchase additional shares pursuant to the Stockholders Agreement. The Company cannot estimate the amount and timing of repurchases that may be required as a result of future stock issuances.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Sep. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefit Plans	'
	Employee Benefit Plans
	The Company has a 401(k) and profit-sharing plan under which annual profit-sharing contributions are determined at the discretion of the board of directors. The Company also makes matching contributions pursuant to the plan document. Profit-sharing and matching contributions expense was $30 million for fiscal year 2014 and $28 million for each of fiscal years 2013 and 2012.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Lease Commitments — The Company has various non-cancelable operating leases on facilities and certain office equipment requiring annual payments as follows (dollars in millions):
	Fiscal Year	Minimum				Sublease				Net Lease
		Lease				Income				Commitments
		Payments
	2015	$	54			$	(1	)		$	53
	2016	53				(2		)		51
	2017	52				(2		)		50
	2018	50				(1		)		49
	2019	46				(1		)		45
	Thereafter (to 2030)	90				—				90
	Total	$	345			$	(7	)		$	338
	A majority of the leases for the Company’s branch offices contain provisions for renewal at the Company’s option. Rental expense, net of sublease income, was approximately $49 million, $54 million and $50 million for fiscal years 2014, 2013 and 2012, respectively.
	Order Routing Litigation — Five putative class action complaints have been filed regarding TD Ameritrade’s routing of client orders. Four cases are pending in the U.S. District Court for the District of Nebraska: Jay Zola et al. v. TD Ameritrade, Inc., et al; Tyler Verdieck v. TD Ameritrade, Inc.; Bruce Lerner v. TD Ameritrade, Inc.; Michael Sarbacker v. TD Ameritrade Holding Corporation, et al. A fifth case is pending in the U.S. District Court for the District of New Jersey: Gerald Klein v. TD Ameritrade Holding Corporation, et al. The complaints in Zola, Klein and Sarbacker allege that the defendants failed to provide clients with “best execution” and routed orders to the market venue that paid the most for its order flow. The complaints in Verdieck and Lerner allege that the defendant routed its clients’ non-marketable limit orders to the venue paying the highest rates of maker rebates, and that clients did not receive best execution on these kinds of orders. The complaints variously include claims of breach of contract, breach of fiduciary duty, breach of the duty of best execution, fraud, negligent misrepresentation, violations of Section 10(b) and 20 of the Exchange Act and SEC Rule 10b-5, violation of Nebraska’s Consumer Protection Act, aiding and abetting, unjust enrichment and declaratory judgment. The complaints seek various kinds of relief including damages, restitution, disgorgement, injunctive relief, equitable relief and other relief. The Company intends to vigorously defend against these lawsuits. The Company is unable to predict the outcome or the timing of the ultimate resolution of these lawsuits, or the potential losses, if any, that may result.
	Reserve Fund Matters — During September 2008, The Reserve, an independent mutual fund company, announced that the net asset value of the Reserve Yield Plus Fund declined below $1.00 per share. The Yield Plus Fund was not a money market mutual fund, but its stated objective was to maintain a net asset value of $1.00 per share. TD Ameritrade, Inc.’s clients continue to hold shares in the Yield Plus Fund (now known as “Yield Plus Fund – In Liquidation”), which is being liquidated. On July 23, 2010, The Reserve announced that through that date it had distributed approximately 94.8% of the Yield Plus Fund assets as of September 15, 2008 and that the Yield Plus Fund had approximately $39.7 million in total remaining assets.  The Reserve stated that the fund’s Board of Trustees has set aside almost the entire amount of the remaining assets to cover potential claims, fees and expenses. The Company estimates that TD Ameritrade, Inc. clients’ current positions held in the Reserve Yield Plus Fund amount to approximately 79% of the fund.
	On January 27, 2011, TD Ameritrade, Inc. entered into a settlement with the SEC, agreeing to pay $0.012 per share to all eligible current or former clients that purchased shares of the Yield Plus Fund and continued to own those shares. Clients who purchased Yield Plus Fund shares through independent registered investment advisors were not eligible for the payment. In February 2011, the Company paid clients approximately $10 million under the settlement agreement.
	In November 2008, a purported class action lawsuit was filed with respect to the Yield Plus Fund. The lawsuit is captioned Ross v. Reserve Management Company, Inc. et al. and is pending in the U.S. District Court for the Southern District of New York. The Ross lawsuit is on behalf of persons who purchased shares of Reserve Yield Plus Fund. On November 20, 2009, the plaintiffs filed a first amended complaint naming as defendants the fund’s advisor, certain of its affiliates and the Company and certain of its directors, officers and shareholders as alleged control persons. The complaint alleges claims of violations of the federal securities laws and other claims based on allegations that false and misleading statements and omissions were made in the Reserve Yield Plus Fund prospectuses and in other statements regarding the fund. The complaint seeks an unspecified amount of compensatory damages including interest, attorneys’ fees, rescission, exemplary damages and equitable relief. On January 19, 2010, the defendants submitted motions to dismiss the complaint. The motions are pending.
	The Company estimates that its clients’ current aggregate shortfall, based on the original par value of their holdings in the Yield Plus Fund, less the value of fund distributions to date and payments to clients under the SEC settlement, is approximately $36 million. This amount does not take into account any assets remaining in the fund that may become available for future distributions.
	The Company is unable to predict the outcome or the timing of the ultimate resolution of the Ross lawsuit, or the potential loss, if any, that may result. However, management believes the outcome is not likely to have a material adverse effect on the financial condition, results of operations or cash flows of the Company.
	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 $30 million as of September 30, 2014. 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 cases as to which an estimate can be made. For certain cases, the Company does not believe an estimate can currently be made, as some cases are in preliminary stages and some cases 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 outcome or the timing of 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 consolidated financial statements could be significantly changed at a later date upon final determinations by taxing authorities. TD has agreed to indemnify the Company for tax obligations, if any, pertaining to activities of TD Waterhouse Group, Inc. (“TD Waterhouse”) prior to the Company’s acquisition of TD Waterhouse in January 2006.
	General Contingencies — In the ordinary course of business, there are various contingencies that are not reflected in the consolidated financial statements. These include the Company’s broker-dealer 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 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 executes 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 cash and securities. 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 purchase or sell financial instruments in the client’s account 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 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 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 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 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):
		September 30,
		2014				2013
	Client margin securities	$	16.2			$	12.5
	Stock borrowings	1				1.2
	Total collateral available	$	17.2			$	13.7
	Collateral loaned	$	2.4			$	1.9
	Collateral repledged	2.5				1.8
	Total collateral loaned or repledged	$	4.9			$	3.7
	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):
				September 30,
	Assets	Balance Sheet Classification		2014				2013
	Cash	Receivable from brokers, dealers and clearing organizations		$	104			$	115
	U.S. government debt securities	Securities owned, at fair value		181				61
	Total			$	285			$	176
	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 potential for the Company to be required to make payments under these agreements is considered remote. Accordingly, no contingent liability is carried on the Consolidated Balance Sheets for these guarantees.
	The Company clears its clients’ futures transactions on an omnibus account basis through unaffiliated clearing firms. The Company has agreed to indemnify the unaffiliated clearing firms for any loss that they may incur for the client transactions introduced to them by the Company.
	See “Insured Deposit Account Agreement” in Note 18 for a description of a guarantee included in that agreement.

Fair_Value_Disclosures

Fair Value Disclosures	12 Months Ended
	Sep. 30, 2014
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, developed based on market data obtained from sources independent of the Company. Unobservable inputs reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability, 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 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 September 30, 2014 and 2013 (dollars in millions):
			As of September 30, 2014
			Level 1		Level 2		Level 3		Fair Value
	Assets:
	Cash equivalents:
	Money market mutual funds		$	1,284	$	—	$	—	$	1,284
	Investments segregated for regulatory purposes:
	U.S. government debt securities		—		3,120		—		3,120
	Securities owned:
	Money market and other mutual funds		—		—		1		1
	U.S. government debt securities		—		326		—		326
	Other		2		3		—		5
	Subtotal - Securities owned		2		329		1		332
	Other assets:
	Pay-variable interest rate swaps(1)		—		32		—		32
	U.S. government debt securities		—		4		—		4
	Auction rate securities		—		—		1		1
	Subtotal - Other assets		—		36		1		37
	Total assets at fair value		$	1,286	$	3,485	$	2	$	4,773
	Liabilities:
	Accounts payable and other liabilities:
	Forward-starting interest rate swaps(2)		$	—	$	29	$	—	$	29
	Securities sold, not yet purchased:
	Equity securities		1		—		—		1
	Total liabilities at fair value		$	1	$	29	$	—	$	30
	-1	See "Fair Value Hedging" in Note 8 for details.
	-2	See "Cash Flow Hedging" in Note 8 for details.
			As of September 30, 2013
			Level 1		Level 2		Level 3		Fair Value
	Assets:
	Cash equivalents:
	Money market mutual funds		$	969	$	—	$	—	$	969
	Investments segregated for regulatory purposes:
	U.S. government debt securities		—		2,045		—		2,045
	Securities owned:
	Auction rate securities		—		—		5		5
	Money market and other mutual funds		—		—		1		1
	U.S. government debt securities		—		313		—		313
	Other		1		3		—		4
	Subtotal - Securities owned		1		316		6		323
	Other assets:
	Equity securities		13		—		—		13
	Pay-variable interest rate swaps(1)		—		52		—		52
	U.S. government debt securities		—		4		—		4
	Subtotal - Other assets		13		56		—		69
	Total assets at fair value		$	983	$	2,417	$	6	$	3,406
	Liabilities:
	Accounts payable and other liabilities:
	Securities sold, not yet purchased:
	Equity securities		$	13	$	—	$	—	$	13
	-1	See "Fair Value Hedging" in Note 8 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 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
Cash and cash equivalents, 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 notes payable are short-term in nature and accordingly are carried at amounts that approximate fair value. Cash and cash equivalents include cash and highly-liquid investments with an original maturity of three months or less (categorized as Level 1 of the fair value hierarchy). 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 notes payable 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 U.S. Treasury 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). In addition, this category includes cash held in demand deposit accounts and on deposit with a futures commission merchant, 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.
Long-term debt — As of September 30, 2014, 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 $1.081 billion, compared to the aggregate carrying value of the Senior Notes on the Consolidated Balance Sheet of $1.032 billion. As of September 30, 2013, the Company’s Senior Notes had an aggregate estimated fair value, based on quoted market prices, of approximately $1.100 billion, compared to the aggregate carrying value of the Senior Notes on the Consolidated Balance Sheet of $1.052 billion.
As of September 30, 2014, the $69 million carrying value of the Company’s variable-rate secured loan approximates fair value because of the frequent repricing of the loan based on market interest rates (categorized as Level 2 of the fair value hierarchy).

Offsetting_Assets_and_Liabilit

Offsetting Assets and Liabilities	12 Months Ended
	Sep. 30, 2014
Offsetting [Abstract]	'
Offsetting Assets and Liabilities	'
	Offsetting Assets and Liabilities
	Substantially all of the Company’s 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 September 30, 2014 and 2013 (dollars in millions):
			September 30, 2014
									Gross Amounts Not Offset
									in the
									Consolidated Balance Sheet
			Gross Amounts		Gross Amounts		Net Amounts		Financial			Collateral			Net
			of Recognized		Offset in the		Presented in		Instruments(3)			Received or			Amount (5)
			Assets and		Consolidated		the Consolidated					Pledged
			Liabilities		Balance Sheet		Balance Sheet					(Including
												Cash) (4)
	Assets:
	Investments segregated for regulatory purposes:
	Reverse repurchase agreements		$	1,193	$	—	$	1,193	$	—		$	(1,193	)	$	—
	Receivable from brokers, dealers and clearing organizations:
	Deposits paid for securities borrowed(1)		995		—		995		(69		)	(900		)	26
	Other assets:
	Pay-variable interest rate swaps		32		—		32		—			(32		)	—
	Total		$	2,220	$	—	$	2,220	$	(69	)	$	(2,125	)	$	26
	Liabilities:
	Payable to brokers, dealers and clearing organizations:
	Deposits received for securities loaned(2)		$	2,384	$	—	$	2,384	$	(69	)	$	(2,015	)	$	300
	Accounts payable and other liabilities:
	Forward-starting interest rate swaps		29		—		29		—			(29		)	—
	Total		$	2,413	$	—	$	2,413	$	(69	)	$	(2,044	)	$	300
			September 30, 2013
									Gross Amounts Not Offset
									in the
									Consolidated Balance Sheet
			Gross Amounts		Gross Amounts		Net Amounts		Financial			Collateral			Net
			of Recognized		Offset in the		Presented in		Instruments(3)			Received or			Amount (5)
			Assets and		Consolidated		the Consolidated					Pledged
			Liabilities		Balance Sheet		Balance Sheet					(Including
												Cash) (4)
	Assets:
	Investments segregated for regulatory purposes:
	Reverse repurchase agreements		$	2,618	$	—	$	2,618	$	—		$	(2,618	)	$	—
	Receivable from brokers, dealers and clearing organizations:
	Deposits paid for securities borrowed(1)		1,220		—		1,220		(168		)	(1,020		)	32
	Other assets:
	Pay-variable interest rate swaps		52		—		52		—			(52		)	—
	Total		$	3,890	$	—	$	3,890	$	(168	)	$	(3,690	)	$	32
	Liabilities:
	Payable to brokers, dealers and clearing organizations:
	Deposits received for securities loaned(2)		$	1,948	$	—	$	1,948	$	(168	)	$	(1,561	)	$	219
	-1	Included in the gross amounts of deposits paid for securities borrowed is $616 million and $702 million as of September 30, 2014 and 2013, respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of cash to the Company.
	-2	Included in the gross amounts of deposits received for securities loaned is $754 million and $275 million as of September 30, 2014 and 2013, respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of securities to the Company.
	-3	Amounts represent recognized assets and liabilities that are subject to enforceable master agreements with rights of setoff.
	-4	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 September 30, 2014 and 2013, the Company had received total collateral with a fair value of $2,231 million and $3,919 million, respectively, and pledged total collateral with a fair value of $2,124 million and $1,721 million, respectively.
	-5	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_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	Accumulated Other Comprehensive Income (Loss)
	The following table presents the net change in fair value recorded for each component of other comprehensive income (loss) before and after income tax for the fiscal years indicated (dollars in millions):
		2014									2013									2012
		Before Tax			Tax Effect			Net of Tax			Before Tax			Tax Effect			Net of Tax			Before Tax		Tax Effect			Net of Tax
	Investments available-for-sale:
	Net unrealized gain	$	—		$	—		$	—		$	21		$	(8	)	$	13		$	28	$	(10	)	$	18
	Reclassification adjustment for net realized gain (1)	—			—			—			(52		)	19			(33		)	—		—			—
	Reclassification of impairment charge (1)	—			—			—			3			(1		)	2			—		—			—
	Change in net unrealized gain	—			—			—			(28		)	10			(18		)	28		(10		)	18
	Cash flow hedging instruments:
	Net unrealized loss	(29		)	11			(18		)	—			—			—			—		—			—
	Other comprehensive income (loss)	$	(29	)	$	11		$	(18	)	$	(28	)	$	10		$	(18	)	$	28	$	(10	)	$	18
	(1) The before tax reclassification amounts and the related tax effects are included in gain on investments, net and provision for income taxes, respectively, on the Consolidated Statements of Income.
	The following table presents after-tax changes in each component of accumulated other comprehensive income (loss) for the fiscal years indicated (dollars in millions):
		2014			2013			2012
	Investments available-for-sale:
	Beginning balance	$	—		$	18		$	—
	Other comprehensive income (loss) before reclassifications	—			13			18
	Amounts reclassified from accumulated other comprehensive income (loss)	—			(31		)	—
	Current period change	—			(18		)	18
	Ending balance	$	—		$	—		$	18
	Cash flow hedging instruments:
	Beginning balance	$	—		$	—		$	—
	Other comprehensive income (loss) before reclassifications	(18		)	—			—
	Amounts reclassified from accumulated other comprehensive income (loss)	—			—			—
	Current period change	(18		)	—			—
	Ending balance	$	(18	)	$	—		$	—
	Total accumulated other comprehensive income (loss):
	Beginning balance	$	—		$	18		$	—
	Other comprehensive income (loss) before reclassifications	(18		)	13			18
	Amounts reclassified from accumulated other comprehensive income (loss)	—			(31		)	—
	Current period change	(18		)	(18		)	18
	Ending balance	$	(18	)	$	—		$	18

Segment_and_Geographic_Area_In

Segment and Geographic Area Information	12 Months Ended
	Sep. 30, 2014
Segment Reporting [Abstract]	'
Segment and Geographic Area Information	'
	Segment and Geographic Area Information
	The Company primarily operates in the securities brokerage industry and has no other reportable segments. Substantially all of the Company’s revenues from external clients for the fiscal years ended September 30, 2014, 2013 and 2012 were derived from its operations in the United States.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	Related Party Transactions
	Transactions with TD and Affiliates
	As a result of the Company’s acquisition of TD Waterhouse during fiscal 2006, TD became an affiliate of the Company. TD owned approximately 41% of the Company’s common stock as of September 30, 2014. Pursuant to the Stockholders Agreement among TD, the Company and certain other stockholders, TD has the right to designate five of 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
	Under the IDA agreement , the TD Depository Institutions make available to clients of the Company FDIC-insured 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 has 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.
	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 September 30, 2014, the IDA portfolio was comprised of approximately 75% fixed-rate notional investments and 25% 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). Under the current IDA agreement, 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%.
	Under the current IDA agreement, 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 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 potential for the marketing fee calculation to result in a negative amount is remote. Accordingly, no contingent liability is carried on the Consolidated Balance Sheets for the IDA agreement.
	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 fiscal years indicated (dollars in millions):
	Description	Statement of Income		Revenues from TD and Affiliates
		Classification		2014				2013		2012
	Insured Deposit Account Agreement	Insured deposit account fees		$	820			$	804	$	828
	Referral and Strategic Alliance Agreement	Various		12				11		8
	Other	Various		5				6		8
	Total revenues			$	837			$	821	$	844
	Description	Statement of Income		Expenses to TD and Affiliates
		Classification		2014				2013		2012
	Canadian Call Center Services Agreement	Professional Services		$	17			$	19	$	18
	Other	Various		3				4		4
	Total expenses			$	20			$	23	$	22
	The following table summarizes the classification and amount of receivables from and payables to TD and its affiliates on the Consolidated Balance Sheets resulting from related party transactions (dollars in millions):
		September 30,
		2014				2013
	Assets:
	Receivable from brokers, dealers and clearing organizations	$	1			$	1
	Receivable from affiliates	99				117
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	96			$	115
	Payable to affiliates	5				4
	Receivables from and payables to brokers, dealers and clearing organizations primarily relate to securities borrowing and 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.

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information	12 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Condensed Consolidating Financial Information	'
	Condensed Consolidating Financial Information
	The 2014 Notes and 2019 Notes are jointly and severally and fully and unconditionally guaranteed by TDAOH. Presented below is condensed consolidating financial information for the Company, its guarantor subsidiary and its non-guarantor subsidiaries for the periods indicated. Because all other comprehensive income (loss) activity occurred on the parent company for all periods presented, condensed consolidating statements of comprehensive income are not presented.
	CONDENSED CONSOLIDATING BALANCE SHEET
	As of September 30, 2014
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	ASSETS
	Cash and cash equivalents	$	117		$	2		$	1,341		$	—		$	1,460
	Cash and investments segregated and on deposit for regulatory purposes	—			—			5,116			—			5,116
	Receivable from brokers, dealers and clearing organizations	—			—			1,108			—			1,108
	Receivable from clients, net	—			—			11,639			—			11,639
	Investments in subsidiaries	5,868			5,754			—			(11,622		)	—
	Receivable from affiliates	11			2			97			(11		)	99
	Goodwill	—			—			2,467			—			2,467
	Acquired intangible assets, net	—			146			605			—			751
	Other, net	156			16			1,073			(54		)	1,191
	Total assets	$	6,152		$	5,920		$	23,446		$	(11,687	)	$	23,831
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	—		$	—		$	2,421		$	—		$	2,421
	Payable to clients	—			—			14,497			—			14,497
	Accounts payable and other liabilities	153			—			455			(13		)	595
	Payable to affiliates	—			—			16			(11		)	5
	Notes payable	150			—			—			—			150
	Long-term debt	1,101			—			—			—			1,101
	Deferred income taxes	—			52			303			(41		)	314
	Total liabilities	1,404			52			17,692			(65		)	19,083
	Stockholders’ equity	4,748			5,868			5,754			(11,622		)	4,748
	Total liabilities and stockholders’ equity	$	6,152		$	5,920		$	23,446		$	(11,687	)	$	23,831
	CONDENSED CONSOLIDATING BALANCE SHEET
	As of September 30, 2013
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	ASSETS
	Cash and cash equivalents	$	199		$	7		$	856		$	—		$	1,062
	Cash and investments segregated and on deposit for regulatory purposes	—			—			5,894			—			5,894
	Receivable from brokers, dealers and clearing organizations	—			—			1,348			—			1,348
	Receivable from clients, net	—			—			8,984			—			8,984
	Investments in subsidiaries	5,568			5,360			550			(11,478		)	—
	Receivable from affiliates	4			3			117			(7		)	117
	Goodwill	—			—			2,467			—			2,467
	Acquired intangible assets, net	—			146			695			—			841
	Other, net	140			9			1,015			(41		)	1,123
	Total assets	$	5,911		$	5,525		$	21,926		$	(11,526	)	$	21,836
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	—		$	—		$	1,973		$	—		$	1,973
	Payable to clients	—			—			13,183			—			13,183
	Accounts payable and other liabilities	180			—			424			(8		)	596
	Payable to affiliates	3			—			8			(7		)	4
	Long-term debt	1,052			—			—			—			1,052
	Deferred income taxes	—			51			334			(33		)	352
	Total liabilities	1,235			51			15,922			(48		)	17,160
	Stockholders’ equity	4,676			5,474			6,004			(11,478		)	4,676
	Total liabilities and stockholders’ equity	$	5,911		$	5,525		$	21,926		$	(11,526	)	$	21,836
	CONDENSED CONSOLIDATING STATEMENT OF INCOME
	For the Year Ended September 30, 2014
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net revenues	$	14		$	—		$	3,123		$	(14	)	$	3,123
Operating expenses	13			—			1,839			(14		)	1,838
Operating income	1			—			1,284			—			1,285
Other expense (income)	24			—			(9		)	—			15
Income (loss) before income taxes and equity in income of subsidiaries	(23		)	—			1,293			—			1,270
Provision for (benefit from) income taxes	(14		)	(1		)	498			—			483
Income (loss) before equity in income of subsidiaries	(9		)	1			795			—			787
Equity in income of subsidiaries	796			787			17			(1,600		)	—
Net income	$	787		$	788		$	812		$	(1,600	)	$	787
CONDENSED CONSOLIDATING STATEMENT OF INCOME
For the Year Ended September 30, 2013
	Parent			Guarantor			Non-Guarantor			Eliminations			Total
				Subsidiary			Subsidiaries
	(In millions)
Net revenues	$	12		$	—		$	2,763		$	(11	)	$	2,764
Operating expenses	10			—			1,709			(11		)	1,708
Operating income	2			—			1,054			—			1,056
Other income	(23		)	—			(9		)	—			(32		)
Income before income taxes and equity in income of subsidiaries	25			—			1,063			—			1,088
Provision for income taxes	8			—			405			—			413
Income before equity in income of subsidiaries	17			—			658			—			675
Equity in income of subsidiaries	658			634			36			(1,328		)	—
Net income	$	675		$	634		$	694		$	(1,328	)	$	675
CONDENSED CONSOLIDATING STATEMENT OF INCOME
For the Year Ended September 30, 2012
	Parent			Guarantor			Non-Guarantor			Eliminations			Total
				Subsidiary			Subsidiaries
	(In millions)
Net revenues	$	32		$	—		$	2,641		$	(32	)	$	2,641
Operating expenses	28			—			1,711			(32		)	1,707
Operating income	4			—			930			—			934
Other expense (income)	29			—			(1		)	—			28
Income (loss) before income taxes and equity in income of subsidiaries	(25		)	—			931			—			906
Provision for (benefit from) income taxes	(19		)	(3		)	342			—			320
Income (loss) before equity in income of subsidiaries	(6		)	3			589			—			586
Equity in income of subsidiaries	592			577			33			(1,202		)	—
Net income	$	586		$	580		$	622		$	(1,202	)	$	586
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
For the Year Ended September 30, 2014
	Parent			Guarantor			Non-Guarantor			Total
				Subsidiary			Subsidiaries
	(In millions)
Net cash provided by (used in) operating activities	$	(81	)	$	1		$	1,105		$	1,025
Cash flows from investing activities:
Purchase of property and equipment	—			—			(144		)	(144		)
Proceeds from sale and maturity of short-term investments	—			—			4			4
Purchase of short-term investments	—			—			(4		)	(4		)
Proceeds from sale of investments	13			—			12			25
Other, net	—			—			2			2
Net cash provided by (used in) investing activities	13			—			(130		)	(117		)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	69			—			—			69
Proceeds from notes payable	230			—			—			230
Principal payments on notes payable	(80		)	—			—			(80		)
Payment of cash dividends	(540		)	—			—			(540		)
Purchase of treasury stock	(207		)	—			—			(207		)
Other, net	18			—			—			18
Net cash used in financing activities	(510		)	—			—			(510		)
Intercompany investing and financing activities, net	496			(6		)	(490		)	—
Net increase (decrease) in cash and cash equivalents	(82		)	(5		)	485			398
Cash and cash equivalents at beginning of year	199			7			856			1,062
Cash and cash equivalents at end of year	$	117		$	2		$	1,341		$	1,460
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
For the Year Ended September 30, 2013
	Parent			Guarantor			Non-Guarantor			Total
				Subsidiary			Subsidiaries
	(In millions)
Net cash provided by (used in) operating activities	$	(70	)	$	1		$	808		$	739
Cash flows from investing activities:
Purchase of property and equipment	—			—			(144		)	(144		)
Proceeds from sale and maturity of short-term investments	150			—			4			154
Purchase of short-term investments	—			—			(4		)	(4		)
Proceeds from sale of investments	78			—			10			88
Other, net	—			—			2			2
Net cash provided by (used in) investing activities	228			—			(132		)	96
Cash flows from financing activities:
Principal payments on long-term debt	(250		)	—			—			(250		)
Proceeds from notes payable	275			—			—			275
Principal payments on notes payable	(275		)	—			—			(275		)
Payment of cash dividends	(471		)	—			—			(471		)
Purchase of treasury stock	(5		)	—			—			(5		)
Other, net	43			—			(5		)	38
Net cash used in financing activities	(683		)	—			(5		)	(688		)
Intercompany investing and financing activities, net	546			—			(546		)	—
Net increase in cash and cash equivalents	21			1			125			147
Cash and cash equivalents at beginning of year	178			6			731			915
Cash and cash equivalents at end of year	$	199		$	7		$	856		$	1,062
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
For the Year Ended September 30, 2012
	Parent			Guarantor			Non-Guarantor			Total
				Subsidiary			Subsidiaries
	(In millions)
Net cash provided by operating activities	$	46		$	2		$	544		$	592
Cash flows from investing activities:
Purchase of property and equipment	—			—			(186		)	(186		)
Purchase of short-term investments	(152		)	—			(3		)	(155		)
Purchase of investments	(43		)	—			(1		)	(44		)
Proceeds from sale of investments	2			—			—			2
Proceeds from sale and maturity of short-term investments	—			—			4			4
Other, net	—			—			2			2
Net cash used in investing activities	(193		)	—			(184		)	(377		)
Cash flows from financing activities:
Purchase of treasury stock	(208		)	—			—			(208		)
Payment of cash dividends	(132		)	—			—			(132		)
Other, net	4			—			4			8
Net cash provided by (used in) financing activities	(336		)	—			4			(332		)
Intercompany investing and financing activities, net	567			(3		)	(564		)	—
Net increase (decrease) in cash and cash equivalents	84			(1		)	(200		)	(117		)
Cash and cash equivalents at beginning of year	94			7			931			1,032
Cash and cash equivalents at end of year	$	178		$	6		$	731		$	915

Quarterly_Data_Unaudited

Quarterly Data (Unaudited)	12 Months Ended
	Sep. 30, 2014
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Data (Unaudited)	'
	Quarterly Data (Unaudited)
	(Dollars in millions, except per share amounts)
			For the Fiscal Year Ended September 30, 2014
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter
	Net revenues		$	752	$	812	$	763	$	795
	Operating income		$	307	$	323	$	316	$	338
	Net income		$	192	$	194	$	190	$	211
	Basic earnings per share		$	0.35	$	0.35	$	0.34	$	0.39
	Diluted earnings per share		$	0.35	$	0.35	$	0.34	$	0.38
			For the Fiscal Year Ended September 30, 2013
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter(1)
	Net revenues		$	651	$	679	$	725	$	709
	Operating income		$	241	$	237	$	298	$	279
	Net income		$	147	$	144	$	184	$	200
	Basic earnings per share		$	0.27	$	0.26	$	0.33	$	0.36
	Diluted earnings per share		$	0.27	$	0.26	$	0.33	$	0.36
	Quarterly amounts may not sum to fiscal year totals due to rounding.
	-1	On July 1, 2013, Knight Capital Group, Inc. ("Knight") completed its merger with GETCO Holding Company, LLC. The Company received merger consideration in exchange for its investment in Knight Class A common stock. The Company’s results of operations for the fourth quarter of fiscal 2013 include a pre-tax gain of $54 million ($34 million after tax, or $0.06 per diluted share) in connection with this transaction, which is included in gain on investments, net on the Consolidated Statements of Income.

Nature_of_Operations_and_Summa1

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation — The consolidated financial statements include the accounts of TD Ameritrade Holding Corporation (the “Parent”), a Delaware corporation, and its wholly-owned subsidiaries (collectively, the “Company”). Intercompany balances and transactions have been eliminated.
Nature of Operations	'
	Nature of Operations — The Company provides securities brokerage services, including trade execution, clearing services and margin lending, through its broker-dealer subsidiaries. The Company provides trustee, custodial and other trust-related services to retirement plans and other custodial accounts through its state-chartered trust company subsidiary. The Company also provides cash sweep and deposit account products through third-party relationships.
	The Company’s broker-dealer subsidiaries are subject to regulation by the Securities and Exchange Commission (“SEC”), the Financial Industry Regulatory Authority (“FINRA”), the Commodity Futures Trading Commission (“CFTC”), the National Futures Association (“NFA”) and the various exchanges in which they maintain membership. Dividends from the Company’s broker-dealer and trust company subsidiaries are a source of liquidity for the holding company. Requirements of the SEC, FINRA and CFTC relating to liquidity, net capital standards and the use of client funds and securities may limit funds available for the payment of dividends from the broker-dealer subsidiaries to the holding company. State regulatory requirements may limit funds available for the payment of dividends from the trust company subsidiary to the holding company.
Use of Estimates	'
	Use of Estimates — The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents — The Company considers temporary, highly-liquid investments with an original maturity of three months or less to be cash equivalents, except for amounts required to be segregated for regulatory purposes.
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 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. Funds can be held in cash, reverse repurchase agreements, U.S. Treasury securities and other qualified securities. Reverse repurchase agreements (securities purchased under agreements to resell) 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 are collateralized by U.S. Treasury securities and generally have a maturity of seven days. Cash and investments segregated and on deposit for regulatory purposes also includes amounts that have been segregated or secured for the benefit of futures clients according to the regulations of the CFTC governing futures commission merchants.
Securities Borrowed and Securities Loaned	'
	Securities Borrowed and Securities Loaned — Securities borrowed and securities loaned transactions are recorded at the amount of cash collateral provided or received. Securities borrowed transactions require the Company to provide the counterparty with collateral in the form of cash. The Company receives collateral in the form of cash for securities loaned transactions. For these transactions, the fees earned or incurred by the Company are recorded as interest revenue and brokerage interest expense, respectively, on the Consolidated Statements of Income. The related interest receivable from and the brokerage interest payable to broker-dealers are included in other receivables and in accounts payable and other liabilities, respectively, on the Consolidated Balance Sheets.
Receivable from/Payable to Clients	'
	Receivable from/Payable to Clients — Receivable from clients primarily consists of margin loans to securities brokerage clients, which are collateralized by client securities, and is carried at the amount receivable, net of an allowance for doubtful accounts that is primarily based on the amount of unsecured margin balances. Payable to clients primarily consists of client cash held in brokerage accounts and is carried at the amount of client cash on deposit. The Company earns interest revenue and pays interest expense on its receivable from client and payable to client balances, respectively. The interest revenue and expense are included in net interest revenue on the Consolidated Statements of Income.
Securities Owned	'
	Securities Owned — Securities owned by our broker-dealer subsidiaries are recorded on a trade-date basis and carried at fair value, and the related changes in fair value are generally included in other revenues on the Consolidated Statements of Income.
Property and Equipment	'
	Property and Equipment — Property and equipment is recorded at cost, net of accumulated depreciation and amortization, except for land, which is recorded at cost. Depreciation is provided using the straight-line method over the estimated useful service lives of the assets, which range from 10 to 40 years for buildings and building components and three to seven years for all other depreciable property and equipment. Leasehold improvements are amortized over the lesser of the economic useful life of the improvement or the term of the lease.
Software Development	'
	Software Development — From the date technological feasibility has been established until beta testing is complete, software development costs are capitalized and included in property and equipment. Once the product is fully functional, such costs are amortized in accordance with the Company’s normal accounting policies. Software development costs that do not meet capitalization criteria are expensed as incurred.
Goodwill	'
	Goodwill — The Company has recorded goodwill for purchase business combinations to the extent the purchase price of each completed acquisition exceeded the fair value of the net identifiable assets of the acquired company. The Company tests goodwill for impairment on at least an annual basis. In performing the impairment tests, the Company utilizes quoted market prices of the Company’s common stock to estimate the fair value of the Company as a whole. The estimated fair value is then allocated to the Company’s reporting units, if applicable, based on operating revenues, and is compared with the carrying value of the reporting units
Amortization of Acquired Intangible Assets	'
	Amortization of Acquired Intangible Assets — Acquired intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives, ranging from three to 23 years. The acquired intangible asset associated with a trademark license agreement is not subject to amortization because the term of the agreement is considered to be indefinite.
Long-Lived Assets and Acquired Intangible Assets	'
	Long-Lived Assets and Acquired Intangible Assets — The Company reviews its long-lived assets and finite-lived acquired intangible assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The Company evaluates recoverability by comparing the undiscounted cash flows associated with the asset to the asset’s carrying amount. The Company also evaluates the remaining useful lives of intangible assets to determine if events or trends warrant a revision to the remaining period of amortization.
	The Company tests its indefinite-lived acquired intangible asset for impairment on at least an annual basis. To determine if the indefinite-lived intangible asset is impaired, the Company first assesses certain qualitative factors. Based on this assessment, if it is determined that more likely than not the fair value of the indefinite-lived intangible asset is less than its carrying amount, the Company performs a quantitative impairment test.
Income Taxes	'
	Income Taxes — The Company files a consolidated U.S. income tax return with its subsidiaries on a calendar year basis, combined returns for state tax purposes where required and certain of its subsidiaries file separate state income tax returns where required. Deferred tax assets and liabilities are determined based on the differences between the financial statement carrying amounts and tax bases of assets and liabilities using enacted tax rates expected to apply to taxable income in the periods in which the deferred tax asset or liability is expected to be settled or realized. Uncertain tax positions are recognized if they are more likely than not to be sustained upon examination, based on the technical merits of the position. The amount of tax benefit recognized is the largest amount of benefit that is greater than 50% likely of being realized upon settlement. The Company recognizes interest and penalties, if any, related to income tax matters as part of the provision for income taxes on the Consolidated Statements of Income.
Capital Stock	'
	Capital Stock — The authorized capital stock of the Company consists of a single class of common stock and one or more series of preferred stock as may be authorized for issuance by the Company’s board of directors. Voting, dividend, conversion and liquidation rights of the preferred stock would be established by the board of directors upon issuance of such preferred stock.
Stock-Based Compensation	'
	Stock-Based Compensation — The Company measures and recognizes compensation expense based on estimated grant date fair values for all stock-based payment arrangements. Stock-based compensation expense is based on awards expected to vest and therefore is reduced for estimated forfeitures. Forfeitures are estimated at the time of grant based on the Company’s historical forfeiture experience and revised in subsequent periods if actual forfeitures differ from those estimates.
Revenue Recognition	'
	Transaction-based Revenues — Client securities trades are recorded on a settlement-date basis with such trades generally settling within three business days after the trade date. Revenues and expenses related to client trades, including order routing revenue (also referred to as payment for order flow) and revenues from markups on riskless principal trades in fixed-income securities, are recorded on a trade-date basis. Revenues related to client trades are recorded net of promotional allowances. Securities owned by clients, including those that collateralize margin or similar transactions, are not reflected in the accompanying consolidated financial statements.
	Net Interest Revenue — Net interest revenue primarily consists of income generated by client cash and interest charged to clients on margin balances, net of interest paid to clients on their credit balances. It also includes net interest revenue from securities borrowed and securities loaned transactions.
	Insured Deposit Account Fees — Insured deposit account fees consist of revenues resulting from the Insured Deposit Account (“IDA”) agreement with TD Bank USA, N.A. (“TD Bank USA”), TD Bank, N.A. and The Toronto-Dominion Bank (“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 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 IDA agreement is described further in Note 18.
	Investment Product Fees — Investment product fee revenue consists of revenues earned on client assets invested in money market mutual funds, other mutual funds and certain Company-sponsored investment programs.
Advertising	'
	Advertising — The Company expenses advertising costs the first time the advertising takes place.
Derivatives and Hedging Activities	'
	Derivatives and Hedging Activities — The Company occasionally utilizes derivative instruments to manage risks, which may include market price, interest rate and foreign currency risks. The Company does not use derivative instruments for speculative or trading purposes. Derivatives are recorded on the Consolidated Balance Sheets as assets or liabilities at fair value. Derivative instruments properly designated to hedge exposure to changes in the fair value of assets or liabilities are accounted for as fair value hedges. Derivative instruments properly designated to hedge exposure to the variability of expected future cash flows or other forecasted transactions are accounted for as cash flow hedges. The Company formally documents the risk management objective and strategy for each hedge transaction. Derivative instruments that do not qualify for hedge accounting are carried at fair value on the Consolidated Balance Sheets with unrealized gains and losses recorded currently on the Consolidated Statements of Income. Cash flows from derivative instruments accounted for as fair value hedges or cash flow hedges are classified in the same category on the Consolidated Statements of Cash Flows as the cash flows from the items being hedged.
Earnings Per Share	'
	Earnings Per Share — Basic earnings per share (“EPS”) is computed by dividing net income by the weighted average common shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock, except when such assumed exercise or conversion would have an antidilutive effect on EPS. The difference between the numerator and denominator used in the Company's computation of basic and diluted earnings per share consists of common stock equivalent shares related to stock-based compensation.
Recently Adopted Accounting Pronouncements	'
	Recently Adopted Accounting Pronouncements
	ASU 2011-11 — On October 1, 2013 the Company retrospectively adopted, for all comparative periods presented, Accounting Standards Update (“ASU”) 2011-11, Disclosures about Offsetting Assets and Liabilities, and ASU 2013-01, Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities. The amendments in these ASUs enhance disclosures by requiring additional information about financial and derivative instruments, including bifurcated embedded derivatives, repurchase agreements and reverse repurchase agreements, and securities borrowing and securities lending transactions that are either (1) offset (netting assets and liabilities) in accordance with Section 210-20-45 or Section 815-10-45 of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification (“ASC”) or (2) subject to an enforceable master netting arrangement or similar agreement. Adoption of ASU 2011-11 and ASU 2013-01 resulted only in the additional disclosures presented in Note 15.
Recently Issued Accounting Pronouncements	'
	Recently Issued Accounting Pronouncements
	ASU 2014-09 — In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers, 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 will supersede 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. An entity may apply the amendments in ASU 2014-09 by using one of the following two methods: (1) retrospective application to each prior reporting period presented or (2) a modified retrospective approach, requiring 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. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. Therefore, ASU 2014-09 will be effective for the Company's fiscal year beginning October 1, 2017. Early adoption is not permitted. The Company is currently assessing the impact that ASU 2014-09 will have on the Company's financial statements and evaluating which adoption method to apply.
	ASU 2014-11 — In June 2014, the FASB issued ASU 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. The amendments in ASU 2014-11 will require entities to account for repurchase-to-maturity transactions and linked repurchase financings as secured borrowings, which is consistent with the accounting for other repurchase agreements. The amendments also require new disclosures, including information regarding collateral pledged in securities lending transactions and similar transactions that are accounted for as secured borrowings. The accounting changes in ASU 2014-11 are effective for the first interim or annual period beginning after December 15, 2014, and the new disclosures related to collateral pledged in transactions that are accounted for as secured borrowings are required to be presented for annual periods beginning after December 15, 2014 and for interim periods beginning after March 15, 2015. Because the Company does not act as a transferor in repurchase-to-maturity transactions or linked repurchase financings, the Company's adoption of ASU 2014-11 is not expected to result in any accounting changes. The new disclosure requirements of ASU 2014-11 will be effective for the Company's fiscal quarter beginning April 1, 2015.
Loss Contingencies (ASC) 450	'
	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.
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, developed based on market data obtained from sources independent of the Company. Unobservable inputs reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability, developed based on the best information available in the circumstances.

Cash_and_Cash_Equivalents_Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Sep. 30, 2014
Cash and Cash Equivalents [Abstract]	'
Summary of Cash and Cash Equivalents	'
	The Company’s cash and cash equivalents is summarized in the following table (dollars in millions):
		September 30,
		2014		2013
	Corporate	$	298	$	429
	Broker-dealer subsidiaries	1,090		540
	Trust company subsidiary	53		74
	Investment advisory subsidiaries	19		19
	Total	$	1,460	$	1,062

Cash_and_Investments_Segregate1

Cash and Investments Segregated and on Deposit for Regulatory Purposes (Tables)	12 Months Ended
	Sep. 30, 2014
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 consists of the following (dollars in millions):
		September 30,
		2014		2013
	U.S. government debt securities	$	3,070	$	1,995
	Reverse repurchase agreements (collateralized by U.S. government debt securities)	1,193		2,618
	Cash in demand deposit accounts	617		1,154
	Cash on deposit with futures commission merchants	186		77
	U.S. government debt securities on deposit with futures commission merchant	50		50
	Total	$	5,116	$	5,894

Receivable_from_and_Payable_to1

Receivable from and Payable to Brokers, Dealers and Clearing Organizations (Tables)	12 Months Ended
	Sep. 30, 2014
Brokers and Dealers [Abstract]	'
Amounts Receivable from and Payable to Brokers, Dealers and Clearing Organizations	'
	Amounts receivable from and payable to brokers, dealers and clearing organizations consist of the following (dollars in millions):
		September 30,
		2014		2013
	Receivable:
	Deposits paid for securities borrowed	$	995	$	1,220
	Broker-dealers	3		9
	Clearing organizations	104		115
	Securities failed to deliver	6		4
	Total	$	1,108	$	1,348
	Payable:
	Deposits received for securities loaned	$	2,384	$	1,948
	Broker-dealers	3		2
	Clearing organizations	23		15
	Securities failed to receive	11		8
	Total	$	2,421	$	1,973

Allowance_for_Doubtful_Account1

Allowance for Doubtful Accounts on Receivables (Tables)	12 Months Ended
	Sep. 30, 2014
Valuation and Qualifying Accounts [Abstract]	'
Allowance for Doubtful Accounts on Client and Other Receivables	'
	The following table summarizes activity in the Company’s allowance for doubtful accounts on client and other receivables for the fiscal years indicated (dollars in millions):
		2014			2013			2012
	Beginning balance	$	15		$	21		$	18
	Provision for (recovery of) doubtful accounts, net	3			(1		)	9
	Write-off of doubtful accounts	(8		)	(5		)	(6		)
	Ending balance	$	10		$	15		$	21

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Sep. 30, 2014
Property, Plant and Equipment [Abstract]	'
Schedule of Property and Equipment	'
	Property and equipment consists of the following (dollars in millions):
		September 30,
		2014			2013
	Buildings and building components	$	264		$	198
	Computer equipment	220			205
	Software	170			144
	Leasehold improvements	156			148
	Land	20			17
	Other property and equipment	72			67
		902			779
	Less: Accumulated depreciation and amortization	(359		)	(282		)
	Property and equipment, net	$	543		$	497

Goodwill_and_Acquired_Intangib1

Goodwill and Acquired Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Acquired Intangible Assets	'
	Acquired intangible assets consist of the following (dollars in millions):
		September 30,
		2014							2013
		Gross		Accumulated			Net		Gross		Accumulated			Net
		Carrying		Amortization			Carrying		Carrying		Amortization			Carrying
		Amount					Amount		Amount					Amount
	Client relationships	$	1,228	$	(645	)	$	583	$	1,228	$	(569	)	$	659
	Technology and content	99		(77		)	22		99		(63		)	36
	Trademark license	146		—			146		146		—			146
		$	1,473	$	(722	)	$	751	$	1,473	$	(632	)	$	841
Estimated Future Amortization Expense for Acquired Intangible Assets	'
	Estimated future amortization expense for acquired intangible assets outstanding as of September 30, 2014 is as follows (dollars in millions):
	Fiscal Year	Estimated
		Amortization
		Expense
	2015	$	90
	2016	85
	2017	76
	2018	72
	2019	68
	Thereafter (to 2025)	214
	Total	$	605

Notes_Payable_and_Longterm_Deb1

Notes Payable and Long-term Debt (Tables)	12 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of Notes Payable and Long Term Debt	'
	Notes payable and long-term debt consist of the following (dollars in millions):
	30-Sep-14	Face				Fair Value				Net Carrying
		Value				Adjustment(1)				Value
	Notes payable:
	Parent Revolving Facility	$	150			$	—			$	150
	Long-term debt:
	Senior Notes:
	4.150% Notes due 2014	500				2				502
	5.600% Notes due 2019	500				30				530
	Secured Loan:
	Variable-rate Note due 2019	69				—				69
	Subtotal - Long-term debt	1,069				32				1,101
	Total notes payable and long-term debt	$	1,219			$	32			$	1,251
	30-Sep-13	Face				Fair Value				Net Carrying
		Value				Adjustment(1)				Value
	Senior Notes:
	4.150% Notes due 2014	$	500			$	15			$	515
	5.600% Notes due 2019	500				37				537
	Total long-term debt	$	1,000			$	52			$	1,052
	(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	'
	Fiscal year maturities on long-term debt outstanding at September 30, 2014 are as follows (dollars in millions):
	2015	$	510
	2016	14
	2017	14
	2018	14
	2019	14
	Thereafter	503
	Total	$	1,069
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 fiscal years indicated (dollars in millions):
		2014				2013				2012
	Gain (loss) on fair value of interest rate swaps	$	(20	)		$	(44	)		$	8
	Gain (loss) on fair value of hedged fixed-rate debt	20				44				(8		)
	Net gain (loss) recorded in interest on borrowings	$	—			$	—			$	—
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block]	'
	The following table summarizes pre-tax losses resulting from changes in the fair value of the forward-starting interest rate swaps for the fiscal years indicated (dollars in millions):
		Amount of Loss Recognized in
		Other Comprehensive Income (Loss)
		(Effective Portion)
		2014				2013				2012
	Forward-starting interest rate swaps	$	(29	)		$	—			$	—
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	'
	The following table summarizes the fair value of outstanding derivatives designated as hedging instruments on the Consolidated Balance Sheets (dollars in millions):
		Balance Sheet Location		September 30,
				2014				2013
	Interest rate contracts:
	Pay-variable interest rate swaps designated as fair value hedges	Other assets		$	32			$	52
	Forward-starting interest rate swaps designated as cash flow hedges	Accounts payable and other liabilities		$	(29	)		$	—

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Provision for Income Taxes	'
	Provision for income taxes is comprised of the following for the fiscal years indicated (dollars in millions):
		2014				2013				2012
	Current expense:
	Federal	$	457			$	370			$	314
	State	53				33				1
		510				403				315
	Deferred expense (benefit):
	Federal	(28		)		(2		)		(2		)
	State	1				12				7
		(27		)		10				5
	Provision for income taxes	$	483			$	413			$	320
Reconciliation of Federal Statutory Tax Rate to Effective Tax Rate	'
	A reconciliation of the federal statutory tax rate to the effective tax rate applicable to pre-tax income follows for the fiscal years indicated:
		2014			2013			2012
	Federal statutory rate	35	%		35	%		35	%
	State taxes, net of federal tax effect	3.1			2.6			2.1
	Adjustments to estimated state income taxes	0.2			0.4			0.1
	Interest recorded on unrecognized tax benefits, net	0.2			0.3			0.1
	Reversal of accruals for unrecognized tax benefits	(0.5	)		(0.3	)		(1.7	)
	Reversal of capital loss valuation allowance	—			—			(0.4	)
	Other	—			—			0.1
		38	%		38	%		35.3	%
Deferred Tax Assets (Liabilities)	'
	Deferred tax assets (liabilities) are comprised of the following (dollars in millions):
		September 30,
		2014				2013
	Deferred tax assets:
	Accrued and other liabilities	$	78			$	72
	Intangible assets, state tax benefit	10				12
	Stock-based compensation	37				36
	Allowance for doubtful accounts	5				6
	Operating loss carryforwards	12				21
	Unrealized loss on cash flow hedging instruments	11				—
	Other deferred tax assets	—				3
	Gross deferred tax assets	153				150
	Less: Valuation allowance	(9		)		(18		)
	Net deferred tax assets	144				132
	Deferred tax liabilities:
	Property and intangible assets	(452		)		(478		)
	Other deferred tax liabilities	(6		)		(5		)
	Total deferred tax liabilities	(458		)		(483		)
	Net deferred tax liabilities	$	(314	)		$	(351	)
Reconciliation of Activity Related to Unrecognized Tax Benefits	'
	A reconciliation of the activity related to unrecognized tax benefits follows for the fiscal years indicated (dollars in millions):
		2014				2013				2012
	Beginning balance	$	137			$	139			$	145
	Additions based on tax positions related to the current year	29				8				10
	Additions for tax positions of prior years	10				2				8
	Reductions for tax positions of prior years	(1		)		(5		)		(3		)
	Reductions due to settlements with taxing authorities	—				(1		)		(5		)
	Reductions due to lapsed statute of limitations	(10		)		(6		)		(16		)
	Ending balance	$	165			$	137			$	139

Capital_Requirements_Tables

Capital Requirements (Tables)	12 Months Ended
	Sep. 30, 2014
Regulatory Capital Requirements [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		Required		Net Capital		Net Capital in		Ratio of Net
		Capital		Net Capital		in Excess of		Excess of		Capital to
				(2% of		Required		Early Warning		Aggregate
				Aggregate		Net Capital		Threshold (5%		Debit Balances
				Debit Balances)				of Aggregate
								Debit Balances)
	September 30, 2014	$	1,569	$	280	$	1,289	$	868	11.19	%
	September 30, 2013	$	1,302	$	222	$	1,080	$	746	11.7	%
	TD Ameritrade, Inc.
	Date	Net		Required		Net Capital		Net Capital in
		Capital		Net Capital		in Excess of		Excess of
				(8% of Total		Required		Early Warning
				Risk Margin)		Net Capital		Threshold
								(110% of
								Required
								Net Capital)
	September 30, 2014	$	347	$	17	$	330	$	328
	September 30, 2013	$	305	$	10	$	295	$	294

Stockbased_Compensation_Tables

Stock-based Compensation (Tables)	12 Months Ended
	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of Option Activity in Stock Incentive Plans	'
	The following is a summary of option activity in the Company’s stock incentive plans for the fiscal year ended September 30, 2014:
		Number of		Weighted		Weighted	Aggregate
		Options		Average		Average	Intrinsic
		(in thousands)		Exercise		Remaining	Value
				Price		Contractual	(in millions)
						Term (Years)
	Outstanding at beginning of year	2,543		$	18.36
	Exercised	(407	)	$	17.98
	Outstanding at end of year	2,136		$	18.43	4	$	32
	Exercisable at end of year	2,136		$	18.43	4	$	32
Summary of Restricted Stock Units Activity in Stock Incentive Plans	'
	The following is a summary of RSU activity in the Company’s stock incentive plans for the fiscal year ended September 30, 2014:
		Number of		Weighted
		Units		Average
		(in thousands)		Grant Date
				Fair Value
	Nonvested at beginning of year	5,351		$	17
	Granted	1,197		$	29.97
	Dividend equivalents	168		$	18.66
	Vested	(1,640	)	$	18.72
	Forfeited	(244	)	$	19.34
	Nonvested at end of year	4,832		$	19.57

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Future Minimum Rental Commitments Under Non-Cancelable Operating Leases	'
	The Company has various non-cancelable operating leases on facilities and certain office equipment requiring annual payments as follows (dollars in millions):
	Fiscal Year	Minimum				Sublease				Net Lease
		Lease				Income				Commitments
		Payments
	2015	$	54			$	(1	)		$	53
	2016	53				(2		)		51
	2017	52				(2		)		50
	2018	50				(1		)		49
	2019	46				(1		)		45
	Thereafter (to 2030)	90				—				90
	Total	$	345			$	(7	)		$	338
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):
		September 30,
		2014				2013
	Client margin securities	$	16.2			$	12.5
	Stock borrowings	1				1.2
	Total collateral available	$	17.2			$	13.7
	Collateral loaned	$	2.4			$	1.9
	Collateral repledged	2.5				1.8
	Total collateral loaned or repledged	$	4.9			$	3.7
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):
				September 30,
	Assets	Balance Sheet Classification		2014				2013
	Cash	Receivable from brokers, dealers and clearing organizations		$	104			$	115
	U.S. government debt securities	Securities owned, at fair value		181				61
	Total			$	285			$	176

Fair_Value_Disclosures_Tables

Fair Value Disclosures (Tables)	12 Months Ended
	Sep. 30, 2014
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 September 30, 2014 and 2013 (dollars in millions):
			As of September 30, 2014
			Level 1		Level 2		Level 3		Fair Value
	Assets:
	Cash equivalents:
	Money market mutual funds		$	1,284	$	—	$	—	$	1,284
	Investments segregated for regulatory purposes:
	U.S. government debt securities		—		3,120		—		3,120
	Securities owned:
	Money market and other mutual funds		—		—		1		1
	U.S. government debt securities		—		326		—		326
	Other		2		3		—		5
	Subtotal - Securities owned		2		329		1		332
	Other assets:
	Pay-variable interest rate swaps(1)		—		32		—		32
	U.S. government debt securities		—		4		—		4
	Auction rate securities		—		—		1		1
	Subtotal - Other assets		—		36		1		37
	Total assets at fair value		$	1,286	$	3,485	$	2	$	4,773
	Liabilities:
	Accounts payable and other liabilities:
	Forward-starting interest rate swaps(2)		$	—	$	29	$	—	$	29
	Securities sold, not yet purchased:
	Equity securities		1		—		—		1
	Total liabilities at fair value		$	1	$	29	$	—	$	30
	-1	See "Fair Value Hedging" in Note 8 for details.
	-2	See "Cash Flow Hedging" in Note 8 for details.
			As of September 30, 2013
			Level 1		Level 2		Level 3		Fair Value
	Assets:
	Cash equivalents:
	Money market mutual funds		$	969	$	—	$	—	$	969
	Investments segregated for regulatory purposes:
	U.S. government debt securities		—		2,045		—		2,045
	Securities owned:
	Auction rate securities		—		—		5		5
	Money market and other mutual funds		—		—		1		1
	U.S. government debt securities		—		313		—		313
	Other		1		3		—		4
	Subtotal - Securities owned		1		316		6		323
	Other assets:
	Equity securities		13		—		—		13
	Pay-variable interest rate swaps(1)		—		52		—		52
	U.S. government debt securities		—		4		—		4
	Subtotal - Other assets		13		56		—		69
	Total assets at fair value		$	983	$	2,417	$	6	$	3,406
	Liabilities:
	Accounts payable and other liabilities:
	Securities sold, not yet purchased:
	Equity securities		$	13	$	—	$	—	$	13
	-1	See "Fair Value Hedging" in Note 8 for details.

Offsetting_Assets_and_Liabilit1

Offsetting Assets and Liabilities (Tables)	12 Months Ended
	Sep. 30, 2014
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 September 30, 2014 and 2013 (dollars in millions):
			September 30, 2014
									Gross Amounts Not Offset
									in the
									Consolidated Balance Sheet
			Gross Amounts		Gross Amounts		Net Amounts		Financial			Collateral			Net
			of Recognized		Offset in the		Presented in		Instruments(3)			Received or			Amount (5)
			Assets and		Consolidated		the Consolidated					Pledged
			Liabilities		Balance Sheet		Balance Sheet					(Including
												Cash) (4)
	Assets:
	Investments segregated for regulatory purposes:
	Reverse repurchase agreements		$	1,193	$	—	$	1,193	$	—		$	(1,193	)	$	—
	Receivable from brokers, dealers and clearing organizations:
	Deposits paid for securities borrowed(1)		995		—		995		(69		)	(900		)	26
	Other assets:
	Pay-variable interest rate swaps		32		—		32		—			(32		)	—
	Total		$	2,220	$	—	$	2,220	$	(69	)	$	(2,125	)	$	26
	Liabilities:
	Payable to brokers, dealers and clearing organizations:
	Deposits received for securities loaned(2)		$	2,384	$	—	$	2,384	$	(69	)	$	(2,015	)	$	300
	Accounts payable and other liabilities:
	Forward-starting interest rate swaps		29		—		29		—			(29		)	—
	Total		$	2,413	$	—	$	2,413	$	(69	)	$	(2,044	)	$	300
			September 30, 2013
									Gross Amounts Not Offset
									in the
									Consolidated Balance Sheet
			Gross Amounts		Gross Amounts		Net Amounts		Financial			Collateral			Net
			of Recognized		Offset in the		Presented in		Instruments(3)			Received or			Amount (5)
			Assets and		Consolidated		the Consolidated					Pledged
			Liabilities		Balance Sheet		Balance Sheet					(Including
												Cash) (4)
	Assets:
	Investments segregated for regulatory purposes:
	Reverse repurchase agreements		$	2,618	$	—	$	2,618	$	—		$	(2,618	)	$	—
	Receivable from brokers, dealers and clearing organizations:
	Deposits paid for securities borrowed(1)		1,220		—		1,220		(168		)	(1,020		)	32
	Other assets:
	Pay-variable interest rate swaps		52		—		52		—			(52		)	—
	Total		$	3,890	$	—	$	3,890	$	(168	)	$	(3,690	)	$	32
	Liabilities:
	Payable to brokers, dealers and clearing organizations:
	Deposits received for securities loaned(2)		$	1,948	$	—	$	1,948	$	(168	)	$	(1,561	)	$	219
	-1	Included in the gross amounts of deposits paid for securities borrowed is $616 million and $702 million as of September 30, 2014 and 2013, respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of cash to the Company.
	-2	Included in the gross amounts of deposits received for securities loaned is $754 million and $275 million as of September 30, 2014 and 2013, respectively, transacted through a risk-sharing program with the OCC, which guarantees the return of securities to the Company.
	-3	Amounts represent recognized assets and liabilities that are subject to enforceable master agreements with rights of setoff.
	-4	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 September 30, 2014 and 2013, the Company had received total collateral with a fair value of $2,231 million and $3,919 million, respectively, and pledged total collateral with a fair value of $2,124 million and $1,721 million, respectively.
	-5	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_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Abstract]	'
Comprehensive Income (Loss)	'
	The following table presents the net change in fair value recorded for each component of other comprehensive income (loss) before and after income tax for the fiscal years indicated (dollars in millions):
		2014									2013									2012
		Before Tax			Tax Effect			Net of Tax			Before Tax			Tax Effect			Net of Tax			Before Tax		Tax Effect			Net of Tax
	Investments available-for-sale:
	Net unrealized gain	$	—		$	—		$	—		$	21		$	(8	)	$	13		$	28	$	(10	)	$	18
	Reclassification adjustment for net realized gain (1)	—			—			—			(52		)	19			(33		)	—		—			—
	Reclassification of impairment charge (1)	—			—			—			3			(1		)	2			—		—			—
	Change in net unrealized gain	—			—			—			(28		)	10			(18		)	28		(10		)	18
	Cash flow hedging instruments:
	Net unrealized loss	(29		)	11			(18		)	—			—			—			—		—			—
	Other comprehensive income (loss)	$	(29	)	$	11		$	(18	)	$	(28	)	$	10		$	(18	)	$	28	$	(10	)	$	18
	(1) The before tax reclassification amounts and the related tax effects are included in gain on investments, net and provision for income taxes, respectively, on the 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 fiscal years indicated (dollars in millions):
		2014			2013			2012
	Investments available-for-sale:
	Beginning balance	$	—		$	18		$	—
	Other comprehensive income (loss) before reclassifications	—			13			18
	Amounts reclassified from accumulated other comprehensive income (loss)	—			(31		)	—
	Current period change	—			(18		)	18
	Ending balance	$	—		$	—		$	18
	Cash flow hedging instruments:
	Beginning balance	$	—		$	—		$	—
	Other comprehensive income (loss) before reclassifications	(18		)	—			—
	Amounts reclassified from accumulated other comprehensive income (loss)	—			—			—
	Current period change	(18		)	—			—
	Ending balance	$	(18	)	$	—		$	—
	Total accumulated other comprehensive income (loss):
	Beginning balance	$	—		$	18		$	—
	Other comprehensive income (loss) before reclassifications	(18		)	13			18
	Amounts reclassified from accumulated other comprehensive income (loss)	—			(31		)	—
	Current period change	(18		)	(18		)	18
	Ending balance	$	(18	)	$	—		$	18

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Sep. 30, 2014
Related Party Transactions [Abstract]	'
Summary of Revenues Resulting from Transactions with Related Parties	'
	The following tables summarize revenues and expenses resulting from transactions with TD and its affiliates for the fiscal years indicated (dollars in millions):
	Description	Statement of Income		Revenues from TD and Affiliates
		Classification		2014				2013		2012
	Insured Deposit Account Agreement	Insured deposit account fees		$	820			$	804	$	828
	Referral and Strategic Alliance Agreement	Various		12				11		8
	Other	Various		5				6		8
	Total revenues			$	837			$	821	$	844
Summary of Expenses Resulting from Transactions with Related Parties	'
	Description	Statement of Income		Expenses to TD and Affiliates
		Classification		2014				2013		2012
	Canadian Call Center Services Agreement	Professional Services		$	17			$	19	$	18
	Other	Various		3				4		4
	Total expenses			$	20			$	23	$	22
Summary of Classification and Amount of Receivables from and Payables to Affiliates of Company	'
	The following table summarizes the classification and amount of receivables from and payables to TD and its affiliates on the Consolidated Balance Sheets resulting from related party transactions (dollars in millions):
		September 30,
		2014				2013
	Assets:
	Receivable from brokers, dealers and clearing organizations	$	1			$	1
	Receivable from affiliates	99				117
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	96			$	115
	Payable to affiliates	5				4

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	12 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Schedule of Condensed Consolidating Balance Sheet	'
	CONDENSED CONSOLIDATING BALANCE SHEET
	As of September 30, 2014
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	ASSETS
	Cash and cash equivalents	$	117		$	2		$	1,341		$	—		$	1,460
	Cash and investments segregated and on deposit for regulatory purposes	—			—			5,116			—			5,116
	Receivable from brokers, dealers and clearing organizations	—			—			1,108			—			1,108
	Receivable from clients, net	—			—			11,639			—			11,639
	Investments in subsidiaries	5,868			5,754			—			(11,622		)	—
	Receivable from affiliates	11			2			97			(11		)	99
	Goodwill	—			—			2,467			—			2,467
	Acquired intangible assets, net	—			146			605			—			751
	Other, net	156			16			1,073			(54		)	1,191
	Total assets	$	6,152		$	5,920		$	23,446		$	(11,687	)	$	23,831
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	—		$	—		$	2,421		$	—		$	2,421
	Payable to clients	—			—			14,497			—			14,497
	Accounts payable and other liabilities	153			—			455			(13		)	595
	Payable to affiliates	—			—			16			(11		)	5
	Notes payable	150			—			—			—			150
	Long-term debt	1,101			—			—			—			1,101
	Deferred income taxes	—			52			303			(41		)	314
	Total liabilities	1,404			52			17,692			(65		)	19,083
	Stockholders’ equity	4,748			5,868			5,754			(11,622		)	4,748
	Total liabilities and stockholders’ equity	$	6,152		$	5,920		$	23,446		$	(11,687	)	$	23,831
	CONDENSED CONSOLIDATING BALANCE SHEET
	As of September 30, 2013
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	ASSETS
	Cash and cash equivalents	$	199		$	7		$	856		$	—		$	1,062
	Cash and investments segregated and on deposit for regulatory purposes	—			—			5,894			—			5,894
	Receivable from brokers, dealers and clearing organizations	—			—			1,348			—			1,348
	Receivable from clients, net	—			—			8,984			—			8,984
	Investments in subsidiaries	5,568			5,360			550			(11,478		)	—
	Receivable from affiliates	4			3			117			(7		)	117
	Goodwill	—			—			2,467			—			2,467
	Acquired intangible assets, net	—			146			695			—			841
	Other, net	140			9			1,015			(41		)	1,123
	Total assets	$	5,911		$	5,525		$	21,926		$	(11,526	)	$	21,836
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Liabilities:
	Payable to brokers, dealers and clearing organizations	$	—		$	—		$	1,973		$	—		$	1,973
	Payable to clients	—			—			13,183			—			13,183
	Accounts payable and other liabilities	180			—			424			(8		)	596
	Payable to affiliates	3			—			8			(7		)	4
	Long-term debt	1,052			—			—			—			1,052
	Deferred income taxes	—			51			334			(33		)	352
	Total liabilities	1,235			51			15,922			(48		)	17,160
	Stockholders’ equity	4,676			5,474			6,004			(11,478		)	4,676
	Total liabilities and stockholders’ equity	$	5,911		$	5,525		$	21,926		$	(11,526	)	$	21,836
Schedule of Condensed Consolidating Statement of Income	'
	CONDENSED CONSOLIDATING STATEMENT OF INCOME
	For the Year Ended September 30, 2014
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net revenues	$	14		$	—		$	3,123		$	(14	)	$	3,123
	Operating expenses	13			—			1,839			(14		)	1,838
	Operating income	1			—			1,284			—			1,285
	Other expense (income)	24			—			(9		)	—			15
	Income (loss) before income taxes and equity in income of subsidiaries	(23		)	—			1,293			—			1,270
	Provision for (benefit from) income taxes	(14		)	(1		)	498			—			483
	Income (loss) before equity in income of subsidiaries	(9		)	1			795			—			787
	Equity in income of subsidiaries	796			787			17			(1,600		)	—
	Net income	$	787		$	788		$	812		$	(1,600	)	$	787
	CONDENSED CONSOLIDATING STATEMENT OF INCOME
	For the Year Ended September 30, 2013
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net revenues	$	12		$	—		$	2,763		$	(11	)	$	2,764
	Operating expenses	10			—			1,709			(11		)	1,708
	Operating income	2			—			1,054			—			1,056
	Other income	(23		)	—			(9		)	—			(32		)
	Income before income taxes and equity in income of subsidiaries	25			—			1,063			—			1,088
	Provision for income taxes	8			—			405			—			413
	Income before equity in income of subsidiaries	17			—			658			—			675
	Equity in income of subsidiaries	658			634			36			(1,328		)	—
	Net income	$	675		$	634		$	694		$	(1,328	)	$	675
	CONDENSED CONSOLIDATING STATEMENT OF INCOME
	For the Year Ended September 30, 2012
		Parent			Guarantor			Non-Guarantor			Eliminations			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net revenues	$	32		$	—		$	2,641		$	(32	)	$	2,641
	Operating expenses	28			—			1,711			(32		)	1,707
	Operating income	4			—			930			—			934
	Other expense (income)	29			—			(1		)	—			28
	Income (loss) before income taxes and equity in income of subsidiaries	(25		)	—			931			—			906
	Provision for (benefit from) income taxes	(19		)	(3		)	342			—			320
	Income (loss) before equity in income of subsidiaries	(6		)	3			589			—			586
	Equity in income of subsidiaries	592			577			33			(1,202		)	—
	Net income	$	586		$	580		$	622		$	(1,202	)	$	586
Schedule of Condensed Consolidating Statement of Cash Flows	'
	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
	For the Year Ended September 30, 2014
		Parent			Guarantor			Non-Guarantor			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net cash provided by (used in) operating activities	$	(81	)	$	1		$	1,105		$	1,025
	Cash flows from investing activities:
	Purchase of property and equipment	—			—			(144		)	(144		)
	Proceeds from sale and maturity of short-term investments	—			—			4			4
	Purchase of short-term investments	—			—			(4		)	(4		)
	Proceeds from sale of investments	13			—			12			25
	Other, net	—			—			2			2
	Net cash provided by (used in) investing activities	13			—			(130		)	(117		)
	Cash flows from financing activities:
	Proceeds from issuance of long-term debt	69			—			—			69
	Proceeds from notes payable	230			—			—			230
	Principal payments on notes payable	(80		)	—			—			(80		)
	Payment of cash dividends	(540		)	—			—			(540		)
	Purchase of treasury stock	(207		)	—			—			(207		)
	Other, net	18			—			—			18
	Net cash used in financing activities	(510		)	—			—			(510		)
	Intercompany investing and financing activities, net	496			(6		)	(490		)	—
	Net increase (decrease) in cash and cash equivalents	(82		)	(5		)	485			398
	Cash and cash equivalents at beginning of year	199			7			856			1,062
	Cash and cash equivalents at end of year	$	117		$	2		$	1,341		$	1,460
	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
	For the Year Ended September 30, 2013
		Parent			Guarantor			Non-Guarantor			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net cash provided by (used in) operating activities	$	(70	)	$	1		$	808		$	739
	Cash flows from investing activities:
	Purchase of property and equipment	—			—			(144		)	(144		)
	Proceeds from sale and maturity of short-term investments	150			—			4			154
	Purchase of short-term investments	—			—			(4		)	(4		)
	Proceeds from sale of investments	78			—			10			88
	Other, net	—			—			2			2
	Net cash provided by (used in) investing activities	228			—			(132		)	96
	Cash flows from financing activities:
	Principal payments on long-term debt	(250		)	—			—			(250		)
	Proceeds from notes payable	275			—			—			275
	Principal payments on notes payable	(275		)	—			—			(275		)
	Payment of cash dividends	(471		)	—			—			(471		)
	Purchase of treasury stock	(5		)	—			—			(5		)
	Other, net	43			—			(5		)	38
	Net cash used in financing activities	(683		)	—			(5		)	(688		)
	Intercompany investing and financing activities, net	546			—			(546		)	—
	Net increase in cash and cash equivalents	21			1			125			147
	Cash and cash equivalents at beginning of year	178			6			731			915
	Cash and cash equivalents at end of year	$	199		$	7		$	856		$	1,062
	CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
	For the Year Ended September 30, 2012
		Parent			Guarantor			Non-Guarantor			Total
					Subsidiary			Subsidiaries
		(In millions)
	Net cash provided by operating activities	$	46		$	2		$	544		$	592
	Cash flows from investing activities:
	Purchase of property and equipment	—			—			(186		)	(186		)
	Purchase of short-term investments	(152		)	—			(3		)	(155		)
	Purchase of investments	(43		)	—			(1		)	(44		)
	Proceeds from sale of investments	2			—			—			2
	Proceeds from sale and maturity of short-term investments	—			—			4			4
	Other, net	—			—			2			2
Net cash used in investing activities	(193		)	—			(184		)	(377		)
Cash flows from financing activities:
Purchase of treasury stock	(208		)	—			—			(208		)
Payment of cash dividends	(132		)	—			—			(132		)
Other, net	4			—			4			8
Net cash provided by (used in) financing activities	(336		)	—			4			(332		)
Intercompany investing and financing activities, net	567			(3		)	(564		)	—
Net increase (decrease) in cash and cash equivalents	84			(1		)	(200		)	(117		)
Cash and cash equivalents at beginning of year	94			7			931			1,032
Cash and cash equivalents at end of year	$	178		$	6		$	731		$	915

Quarterly_Data_Unaudited_Table

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2014
Quarterly Financial Information Disclosure [Abstract]	'
Schedule of Quarterly Financial Data	'
	(Dollars in millions, except per share amounts)
			For the Fiscal Year Ended September 30, 2014
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter
	Net revenues		$	752	$	812	$	763	$	795
	Operating income		$	307	$	323	$	316	$	338
	Net income		$	192	$	194	$	190	$	211
	Basic earnings per share		$	0.35	$	0.35	$	0.34	$	0.39
	Diluted earnings per share		$	0.35	$	0.35	$	0.34	$	0.38
			For the Fiscal Year Ended September 30, 2013
			First		Second		Third		Fourth
			Quarter		Quarter		Quarter		Quarter(1)
	Net revenues		$	651	$	679	$	725	$	709
	Operating income		$	241	$	237	$	298	$	279
	Net income		$	147	$	144	$	184	$	200
	Basic earnings per share		$	0.27	$	0.26	$	0.33	$	0.36
	Diluted earnings per share		$	0.27	$	0.26	$	0.33	$	0.36
	Quarterly amounts may not sum to fiscal year totals due to rounding.
	-1	On July 1, 2013, Knight Capital Group, Inc. ("Knight") completed its merger with GETCO Holding Company, LLC. The Company received merger consideration in exchange for its investment in Knight Class A common stock. The Company’s results of operations for the fourth quarter of fiscal 2013 include a pre-tax gain of $54 million ($34 million after tax, or $0.06 per diluted share) in connection with this transaction, which is included in gain on investments, net on the Consolidated Statements of Income.

Nature_of_Operations_and_Summa2

Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Maturity period of cash equivalents (three months or less)	'3 months	'	'
General maturity of the Company's reverse repurchase agreements which are collateralized by U.S. Treasury securities	'7 days	'	'
The amount of impairment charges that have resulted from the goodwill annual impairment tests	$0	'	'
Estimated useful service life of acquired intangible assets, minimum, in years	'3 years	'	'
Estimated useful service life of acquired intangible assets, maximum, in years	'23 years	'	'
The amount of impairment charges that have resulted from the intangible assets annual impairment tests	$0	'	'
Number of business days that client securities transactions generally settle within (in business days)	'3 days	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	700,000	2,500,000
Minimum [Member]	'	'	'
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Percent likelihood for tax benefit amounts to be realized upon settlement	50.00%	'	'
Minimum [Member] | All Other Depreciable Property and Equipment [Member]	'	'	'
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Estimated useful service lives	'3 years	'	'
Minimum [Member] | Building and Building Components [Member]	'	'	'
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Estimated useful service lives	'10 years	'	'
Maximum [Member] | All Other Depreciable Property and Equipment [Member]	'	'	'
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Estimated useful service lives	'7 years	'	'
Maximum [Member] | Building and Building Components [Member]	'	'	'
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]	'	'	'
Estimated useful service lives	'40 years	'	'

Cash_and_Cash_Equivalents_Summ

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
In Millions, unless otherwise specified
Cash and Cash Equivalents [Line Items]	'	'	'	'
Cash and cash equivalents	$1,460	$1,062	$915	$1,032
Corporate [Member]	'	'	'	'
Cash and Cash Equivalents [Line Items]	'	'	'	'
Cash and cash equivalents	298	429	'	'
Broker-dealer subsidiaries [Member]	'	'	'	'
Cash and Cash Equivalents [Line Items]	'	'	'	'
Cash and cash equivalents	1,090	540	'	'
Trust company subsidiary [Member]	'	'	'	'
Cash and Cash Equivalents [Line Items]	'	'	'	'
Cash and cash equivalents	53	74	'	'
Investment advisory subsidiaries [Member]	'	'	'	'
Cash and Cash Equivalents [Line Items]	'	'	'	'
Cash and cash equivalents	$19	$19	'	'

Cash_and_Investments_Segregate2

Cash and Investments Segregated and on Deposit for Regulatory Purposes (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Cash and investments segregated and on deposit for regulatory purposes	$5,116	$5,894
U.S. Government Debt Securities [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Cash and investments segregated and on deposit for regulatory purposes	3,070	1,995
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	1,193	2,618
Cash in Demand Deposit Accounts [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Cash and investments segregated and on deposit for regulatory purposes	617	1,154
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	186	77
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	$50	$50

Receivable_from_and_Payable_to2

Receivable from and Payable to Brokers, Dealers and Clearing Organizations - Amounts Receivable from and Payable to Brokers, Dealers and Clearing Organizations (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Receivable:	'	'
Deposits paid for securities borrowed	$995	$1,220
Broker-dealers	3	9
Clearing organizations	104	115
Securities failed to deliver	6	4
Total	1,108	1,348
Payable:	'	'
Deposits received for securities loaned	2,384	1,948
Broker-dealers	3	2
Clearing organizations	23	15
Securities failed to receive	11	8
Total	$2,421	$1,973

Allowance_for_Doubtful_Account2

Allowance for Doubtful Accounts on Client and Other Receivables (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Valuation and Qualifying Accounts [Abstract]	'	'	'
Beginning balance	$15	$21	$18
Provision for (recovery of) doubtful accounts, net	3	-1	9
Write-off of doubtful accounts	-8	-5	-6
Ending balance	$10	$15	$21

Property_and_Equipment_Schedul

Property and Equipment - Schedule of Property and Equipment (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment [Abstract]	'	'
Building and building components	$264	$198
Computer equipment	220	205
Software	170	144
Leasehold improvements	156	148
Land	20	17
Other property and equipment	72	67
Property and equipment, gross	902	779
Less: Accumulated depreciation and amortization	-359	-282
Property and equipment, net	$543	$497

Goodwill_and_Acquired_Intangib2

Goodwill and Acquired Intangible Assets - Acquired Intangible Assets (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Acquired Intangible Assets [Line Items]	'	'
Gross Carrying Amount	$1,473	$1,473
Accumulated Amortization	-722	-632
Net Carrying Amount	751	841
Client relationships [Member]	'	'
Acquired Intangible Assets [Line Items]	'	'
Gross Carrying Amount	1,228	1,228
Accumulated Amortization	-645	-569
Net Carrying Amount	583	659
Technology and content [Member]	'	'
Acquired Intangible Assets [Line Items]	'	'
Gross Carrying Amount	99	99
Accumulated Amortization	-77	-63
Net Carrying Amount	22	36
Trademark license [Member]	'	'
Acquired Intangible Assets [Line Items]	'	'
Gross Carrying Amount	146	146
Accumulated Amortization	0	0
Net Carrying Amount	$146	$146

Goodwill_and_Acquired_Intangib3

Goodwill and Acquired Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'
Amortization expense on acquired intangible assets	$90	$91	$92

Goodwill_and_Acquired_Intangib4

Goodwill and Acquired Intangible Assets - Estimated Future Amortization Expense for Acquired Intangible Assets (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Goodwill and Intangible Assets Disclosure [Abstract]	'
2015	$90
2016	85
2017	76
2018	72
2019	68
Thereafter (to 2025)	214
Total	$605

Notes_Payable_and_Longterm_Deb2

Notes Payable and Long-term Debt - Schedule of Notes Payable and Long-term Debt (Detail) (USD $)	Sep. 30, 2014	Nov. 25, 2009	Nov. 25, 2009	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014
		4.150% Senior Notes due 2014 [Member]	5.600% Senior Notes due 2019 [Member]	Notes Payable Parent Revolving Facility [Member]	Long-term Debt [Member]	Long-term Debt [Member]	Long-term Debt [Member]	Long-term Debt [Member]	Long-term Debt [Member]	Long-term Debt [Member]	Long-term Debt [Member]
							4.150% Senior Notes due 2014 [Member]	4.150% Senior Notes due 2014 [Member]	5.600% Senior Notes due 2019 [Member]	5.600% Senior Notes due 2019 [Member]	Variable-rate Note due 2019 [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Face Value	$1,219,000,000	$500,000,000	$500,000,000	$150,000,000	$1,069,000,000	$1,000,000,000	$500,000,000	$500,000,000	$500,000,000	$500,000,000	$69,000,000
Fair Value Adjustment	32,000,000	'	'	'	32,000,000	52,000,000	2,000,000	15,000,000	30,000,000	37,000,000	'
Net Carrying Value	$1,251,000,000	'	'	$150,000,000	$1,101,000,000	$1,052,000,000	$502,000,000	$515,000,000	$530,000,000	$537,000,000	$69,000,000

Notes_Payable_and_Longterm_Deb3

Notes Payable and Long-term Debt - Fiscal Year Maturities on Long-term Debt Outstanding (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Debt Disclosure [Abstract]	'
2015	$510
2016	14
2017	14
2018	14
2019	14
Thereafter	503
Total	$1,069

Notes_Payable_and_Longterm_Deb4

Notes Payable and Long-term Debt - Senior Notes and Secured Loan - Additional Information (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2014	Nov. 25, 2009	Sep. 30, 2014	Nov. 25, 2009	Sep. 30, 2014	Sep. 15, 2014	Dec. 31, 2014	Oct. 17, 2014
		2014 Notes and 2019 Notes [Member]	4.150% Senior Notes due 2014 [Member]	4.150% Senior Notes due 2014 [Member]	5.600% Senior Notes due 2019 [Member]	5.600% Senior Notes due 2019 [Member]	Secured Loan [Member]	Secured Loan [Member]	Subsequent Event [Member]	Subsequent Event [Member]
									3.625% Senior Notes due 2025 [Member]	3.625% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'	'
Debt Instrument, Face Amount	$1,219,000,000	'	'	$500,000,000	'	$500,000,000	'	$69,000,000	'	$500,000,000
Debt instrument interest rate stated percentage	'	'	4.15%	'	5.60%	'	'	'	'	3.63%
Due date of Senior Notes	'	'	1-Dec-14	'	1-Dec-19	'	1-Oct-19	'	1-Apr-25	'
Debt Instrument, Offering Date	'	25-Nov-09	'	'	'	'	'	'	17-Oct-14	'
Senior Notes redemption price in percentage based on principal amount of Note	'	100.00%	'	'	'	'	'	'	100.00%	'
Discount rate for redemption of Senior Notes principal and interest, comparable to U.S. Treasury rate plus basis points	'	'	0.30%	'	0.35%	'	'	'	'	0.25%
Note Four Date That Determines Redemption Price	'	'	'	'	'	'	'	'	1-Jan-25	'
Debt Instrument, Frequency of Periodic Payment	'	'	'	'	'	'	'20 consecutive quarterly	'	'	'
Debt Instrument, Date of First Required Payment	'	'	'	'	'	'	1-Jan-15	'	'	'
Secured Loan Interest Rate Basis Term Of Libor	'	'	'	'	'	'	'1 month	'	'	'
Secured Loan Interest Rate In Points Over And Above Libor	'	'	'	'	'	'	'	1.38%	'	'
Secured Loan Interest Rate at period end	'	'	'	'	'	'	1.53%	'	'	'

Notes_Payable_and_Longterm_Deb5

Notes Payable and Long-term Debt - Fair Value Hedging - Additional Information (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2014	Dec. 30, 2009	Jan. 07, 2011	Dec. 31, 2014	Nov. 19, 2014
	Senior Notes [Member]	Pay Variable Interest Rate Swap [Member]	Pay Variable Interest Rate Swap [Member]	Pay Variable Interest Rate Swap [Member]	Subsequent Event [Member]	Subsequent Event [Member]
			4.150% Senior Notes due 2014 [Member]	5.600% Senior Notes due 2019 [Member]	Pay Variable Interest Rate Swap [Member]	Pay Variable Interest Rate Swap [Member]
						3.625% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'
Notional amount of interest rate swaps on Notes	'	'	$500,000,000	$500,000,000	'	$500,000,000
Interest rate swap, variable rate basis	'	'three-month LIBOR	'	'	'three-month LIBOR	'
Variable interest rate on swaps in excess of LIBOR rate, percentage	'	'	1.25%	2.37%	'	1.10%
Weighted-average effective interest rate	2.04%	'	'	'	'	'

Notes_Payable_and_Longterm_Deb6

Notes Payable and Long-term Debt - Gains and Losses Resulting from Changes in Fair Value of Interest Rate Swaps and Hedged Fixed Rate Debt (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Debt Disclosure [Abstract]	'	'	'
Gain (loss) on fair value of interest rate swaps	($20)	($44)	$8
Gain (loss) on fair value of hedged fixed-rate debt	20	44	-8
Net gain (loss) recorded in interest on borrowings	$0	$0	$0

Notes_Payable_and_Longterm_Deb7

Notes Payable and Long-term Debt - Cash Flow Hedging - Additional Information (Details) (USD $)	Sep. 30, 2014	Jan. 17, 2014	Sep. 30, 2014	Dec. 31, 2014	Oct. 17, 2014	Oct. 17, 2014
		Forward Starting Interest Rate Swap [Member]	Forward Starting Interest Rate Swap [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
				Forward Starting Interest Rate Swap [Member]	Forward Starting Interest Rate Swap [Member]	3.625% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'
Forward-starting interest rate swap contract settlement date range - start	'	17-Jan-14	'	'	'	'
Aggregate notional amount of forward-starting interest rate swap contracts	'	$500,000,000	'	'	'	'
Debt Instrument, Face Amount	1,219,000,000	'	'	'	'	500,000,000
Amount Paid To Settle Forward Starting Interest Rate Swap Contracts	'	'	'	'	45,000,000	'
Loss on Cash Flow Hedge Ineffectiveness	'	'	'	500,000	'	'
Amount of Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	'	'	$4,400,000	'	'	'
Description of Reclassification of Interest Rate Cash Flow Hedge Gain (Loss)	'	'	'12 months	'	'	'

Notes_Payable_and_Longterm_Deb8

Notes Payable and Long-term Debt - Effective Portion of Cash Flow Hedge (Details) (Forward Starting Interest Rate Swap [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Forward Starting Interest Rate Swap [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	($29)	$0	$0

Notes_Payable_and_Longterm_Deb9

Notes Payable and Long-term Debt - Fair Value of Outstanding Derivatives Designated as Hedging Instruments (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Derivatives recorded under the caption Other assets	'	'
Pay-variable interest rate swaps designated as fair value hedges	$32	$52
Derivatives recorded under the caption Accounts Payable And Other Liabilities	'	'
Forward-starting interest rate swaps designated as cash flow hedges	($29)	$0

Recovered_Sheet1

Notes Payable and Long-term Debt - Balance Sheet Impact of Hedging Instruments - Additional Information (Details) (Cash [Member], USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Forward Starting Interest Rate Swap [Member]	'	'
Debt Instrument [Line Items]	'	'
Pledged Collateral To The Interest Rate Swap Counterparty	$43	'
Pay Variable Interest Rate Swap [Member]	'	'
Debt Instrument [Line Items]	'	'
Pledged Collateral From Interest Rate Swap Counter Party Aggregate Fair Value	$47	$67

Recovered_Sheet2

Notes Payable and Long-term Debt - TD Ameritrade Holding Corporation and Clearing, Inc Credit Agreement - Additional Information (Detail) (USD $)

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Jun. 11, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Jun. 11, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Jun. 28, 2011

Sep. 30, 2014

Sep. 30, 2013

Jun. 28, 2011

TD Ameritrade Holding Corporation [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Senior Unsecured Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

Prior Revolving Credit Facility [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Holding Corporation [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

TD Ameritrade Clearing, Inc. [Member]

Minimum [Member]

Maximum [Member]

Federal Funds Rate [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

Base Rate [Member]

Base Rate [Member]

Base Rate [Member]

Minimum [Member]

Maximum [Member]

Federal Funds Rate [Member]

Federal Funds Rate [Member]

Federal Funds Rate [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Initiation Date

'

'

'

11-Jun-14

'

'

'

'

'

'

'

'

'

'

11-Jun-14

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Senior unsecured revolving credit facility, aggregate principal amount

'

'

'

'

$300,000,000

'

'

'

'

'

'

'

'

'

'

$300,000,000

'

'

'

'

'

'

'

'

'

'

$300,000,000

'

'

$300,000,000

Line of credit facility expiration date

'

'

'

11-Jun-19

'

'

'

'

'

'

'

'

'

'

11-Jun-19

'

'

'

'

'

'

'

'

'

28-Jun-14

'

'

28-Jun-14

'

'

Interest rate margin for LIBOR loans

'

'

'

'

'

'

'

0.50%

1.25%

0.88%

1.75%

1.00%

0.00%

0.75%

'

'

'

'

1.00%

0.75%

1.50%

1.00%

0.75%

1.50%

'

'

'

'

'

'

Debt instrument basis spread on variable rate

'

'

'

'one-month LIBOR

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Commitment Fee Percentage

'

'

'

0.15%

'

0.10%

0.25%

'

'

'

'

'

'

'

0.13%

'

0.08%

0.20%

'

'

'

'

'

'

'

'

'

'

'

'

Borrowings outstanding under the Revolving Credit Facility

$150,000,000

$0

$150,000,000

$150,000,000

'

'

'

'

'

'

'

'

'

'

$0

'

'

'

'

'

'

'

'

'

'

$0

'

'

$0

'

Senior unsecured revolving credit facility, interest rate at period end

'

'

'

'

'

'

'

'

1.40%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Income_Taxes_Provision_for_Inc

Income Taxes - Provision for Income Taxes (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Current expense :	'	'	'
Federal	$457	$370	$314
State	53	33	1
Total	510	403	315
Deferred expense (benefit):	'	'	'
Federal	-28	-2	-2
State	1	12	7
Total	-27	10	5
Provision for income taxes	$483	$413	$320

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Statutory Tax Rate to Effective Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'
Federal statutory rate	35.00%	35.00%	35.00%
State taxes, net of federal tax effect	3.10%	2.60%	2.10%
Adjustments to estimated state income taxes	0.20%	0.40%	0.10%
Interest recorded on unrecognized tax benefits, net	0.20%	0.30%	0.10%
Reversal of accruals for unrecognized tax benefits	-0.50%	-0.30%	-1.70%
Reversal of capital loss valuation allowance	0.00%	0.00%	-0.40%
Other	0.00%	0.00%	0.10%
Effective income tax rate	38.00%	38.00%	35.30%

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Line Items]	'	'	'	'
Effective income tax rate	38.00%	38.00%	35.30%	'
Favorable resolutions of certain income tax matters	$10	$6	$19	'
Unfavorable deferred income tax adjustments	2	4	'	'
Favorable per share impact on earnings	$0.01	'	$0.04	'
Benefit from reversal of valuation allowance related to capital loss carryover	'	'	3	'
Deferred tax benefits relating to intangible asset amortization deductions	1	1	'	'
Federal net operating loss carryover acquired in thinkorswim acquisition	3	'	'	'
Federal net operating loss carryover acquired in thinkorswim acquisition, expiration year	'2019	'	'	'
Subsidiaries state operating loss carryforwards	173	'	'	'
Decrease in the valuation allowance	9	'	'	'
Unrecognized tax benefits	165	137	139	145
Unrecognized tax benefits net of federal benefit on state matters	107	89	'	'
Unrecognized tax benefits net of federal benefit on state matters that would Impact effective tax rate	107	89	'	'
Statute of Limitations Period, Minimum (In years)	'3 years	'	'	'
Statute of Limitations Period, Maximum (In years)	'4 years	'	'	'
Reasonably possible reduction in unrecognized tax benefits	49	'	'	'
Reasonably possible reduction in unrecognized tax benefits net of federal benefit on state matters	32	'	'	'
Interest and penalties expense (benefit) recognized	3	2	-3	'
Accrued interest and penalties related to unrecognized tax benefits	$53	$48	'	'
Minimum [Member]	'	'	'	'
Income Taxes [Line Items]	'	'	'	'
Subsidiaries state operating loss carryforwards, expiration year	'2015	'	'	'
Federal return years that remain open under the statute of limitations	'2011	'	'	'
Maximum [Member]	'	'	'	'
Income Taxes [Line Items]	'	'	'	'
Subsidiaries state operating loss carryforwards, expiration year	'2033	'	'	'
Federal return years that remain open under the statute of limitations	'2013	'	'	'

Income_Taxes_Deferred_Tax_Asse

Income Taxes - Deferred Tax Assets (Liabilities) (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Deferred tax assets:	'	'
Accrued and other liabilities	$78	$72
Intangible assets, state tax benefit	10	12
Stock-based compensation	37	36
Allowance for doubtful accounts	5	6
Operating loss carryforwards	12	21
Unrealized loss on cash flow hedging instruments	11	0
Other deferred tax assets	0	3
Gross deferred tax assets	153	150
Less: Valuation allowance	-9	-18
Net deferred tax assets	144	132
Deferred tax liabilities:	'	'
Property and intangible assets	-452	-478
Other deferred tax liabilities	-6	-5
Total deferred tax liabilities	-458	-483
Net deferred tax liabilities	($314)	($351)

Income_Taxes_Reconciliation_of1

Income Taxes - Reconciliation of Activity Related to Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'
Beginning balance	$137	$139	$145
Additions based on tax positions related to the current year	29	8	10
Additions for tax positions of prior years	10	2	8
Reductions for tax positions of prior years	-1	-5	-3
Reductions due to settlements with taxing authorities	0	-1	-5
Reductions due to lapsed statute of limitations	-10	-6	-16
Ending balance	$165	$137	$139

Capital_Requirements_Additiona

Capital Requirements - Additional Information (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
Net Capital and Net Capital Requirements For Company's Broker Dealer Subsidiaries [Line Items]	'	'
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%	'
Percentage of net capital to the Company's risk based capital 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	110.00%	'
Percentage of net capital to the Company's 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 Trust Company's Tier 1 capital	$27,000,000	$23,000,000
Amount in excess of required Tier 1 capital	12,000,000	8,000,000
TD Ameritrade Clearing, Inc. [Member]	'	'
Net Capital and Net Capital Requirements For Company's Broker Dealer Subsidiaries [Line Items]	'	'
Minimum net capital required	1,500,000	'
Percentage of aggregate debit balances required as minimum net capital	2.00%	'
TD Ameritrade, Inc. [Member]	'	'
Net Capital and Net Capital Requirements For Company's Broker Dealer Subsidiaries [Line Items]	'	'
Minimum net capital required	250,000	'
Percentage of aggregate debit balances required as minimum net capital	2.00%	'
Net capital required under Regulation 1.17 of the Commodity Exchange Act	$1,000,000	'
Minimum percentage of the total risk margin requirements for all positions carried in non-client accounts to be added to the minimum percentage of the total risk margin requirements for all positions carried in client accounts for minimum net capital calculation	8.00%	'
Minimum percentage of the total risk margin requirements for all positions carried in client accounts to be added to the minimum percentage of the total risk margin requirements for all positions carried in non-client accounts for minimum net capital calculation	8.00%	'

Capital_Requirements_Net_Capit

Capital Requirements - Net Capital and Net Capital Requirements for Company's Broker-dealer Subsidiaries (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
TD Ameritrade Clearing, Inc. [Member]	'	'
Net Capital and Net Capital Requirements For Company's Broker Dealer Subsidiaries [Line Items]	'	'
Net Capital	$1,569	$1,302
Required Net Capital	280	222
Net Capital in Excess of Required Net Capital	1,289	1,080
Net Capital in Excess of Early Warning Threshold	868	746
Ratio of Net Capital to Aggregate Debit Balances	11.19%	11.70%
TD Ameritrade, Inc. [Member]	'	'
Net Capital and Net Capital Requirements For Company's Broker Dealer Subsidiaries [Line Items]	'	'
Net Capital	347	305
Required Net Capital	17	10
Net Capital in Excess of Required Net Capital	330	295
Net Capital in Excess of Early Warning Threshold	$328	$294

Stockbased_Compensation_Additi

Stock-based Compensation - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
	stock_incentive_plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of stock incentive plans	2	'	'
Expiration period of stock options from grant date	'10 years	'	'
Stock-based compensation expense	$32,000,000	$29,000,000	$41,000,000
Income tax benefits	12,000,000	11,000,000	15,000,000
Number of options granted	0	0	0
Total intrinsic value of options exercised	6,000,000	65,000,000	21,000,000
Unrecognized compensation cost related to nonvested stock option awards	0	'	'
Stock Options [Member] | Minimum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period	'1 year	'	'
Stock Options [Member] | Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period	'4 years	'	'
Restricted Stock Units (RSUs) [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Total unrecognized compensation costs related to nonvested stock-based compensation awards	$27,000,000	'	'
Weighted average period of recognition of unrecognized compensation cost related to nonvested stock-based compensation awards	'1 year 9 months 18 days	'	'
Restricted Stock Units (RSUs) [Member] | Employees [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period	'3 years	'	'
Restricted Stock Units (RSUs) [Member] | Non-employee directors [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period	'1 year	'	'
Long-Term Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Company's common stock reserved for issuance to employee	42,104,174	'	'
2006 Directors Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Company's common stock reserved for issuance to employee	1,830,793	'	'

Stockbased_Compensation_Summar

Stock-based Compensation - Summary of Option Activity in Stock Incentive Plans (Detail) (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Number of Options, Outstanding at beginning of year (in shares)	2,543
Number of Options, Exercised (in shares)	-407
Number of Options, Outstanding at end of year (in shares)	2,136
Number of Options, Exercisable at end of year (in shares)	2,136
Weighted Average Exercise Price, Outstanding at beginning of year (in dollars per share)	$18.36
Weighted Average Exercise Price, Exercised (in dollars per share)	$17.98
Weighted Average Exercise Price, Outstanding at end of year (in dollars per share)	$18.43
Weighted Average Exercise Price, Exercisable at end of year (in dollars per share)	$18.43
Weighted Average Remaining Contractual Term, Outstanding at end of year (in years)	'4 years
Weighted Average Remaining Contractual Term, Exercisable at end of year (in years)	'4 years
Aggregate Intrinsic Value, Outstanding at end of year (in dollars)	$32
Aggregate Intrinsic Value, Exercisable at end of year (in dollars)	$32

Stockbased_Compensation_Summar1

Stock-based Compensation - Summary of Restricted Stock Units Activity in Stock Incentive Plans (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Number of Units, Nonvested at beginning of year	5,351
Number of Units, Granted	1,197
Number of Units, Dividend equivalents	168
Number of Units, Vested	-1,640
Number of Units, Forfeited	-244
Number of Units, Nonvested at end of year	4,832
Weighted Average Grant Date Fair Value, Nonvested at beginning of year (in dollars per share)	$17
Weighted Average Grant Date Fair Value, Granted (in dollars per share)	$29.97
Weighted Average Grant Date Fair Value, Dividend equivalents (in dollars per share)	$18.66
Weighted Average Grant Date Fair Value, Vested (in dollars per share)	$18.72
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share)	$19.34
Weighted Average Grant Date Fair Value, Nonvested at end of year (in dollars per share)	$19.57

Employee_Benefit_Plans_Additio

Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Compensation and Retirement Disclosure [Abstract]	'	'	'
Profit-sharing and matching contributions expense	$30	$28	$28

Commitments_and_Contingencies_1

Commitments and Contingencies - Future Minimum Rental Commitments Under Non-Cancelable Operating Leases (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Minimum Lease Payments 2015	$54
Minimum Lease Payments 2016	53
Minimum Lease Payments 2017	52
Minimum Lease Payments 2018	50
Minimum Lease Payments 2019	46
Minimum Lease Payments Thereafter (to 2030)	90
Total Minimum Lease Payments	345
Sublease Income 2015	-1
Sublease Income 2016	-2
Sublease Income 2017	-2
Sublease Income 2018	-1
Sublease Income 2019	-1
Sublease Income Thereafter (to 2030)	0
Total Sublease Income	-7
Net Lease Commitments 2015	53
Net Lease Commitments 2016	51
Net Lease Commitments 2017	50
Net Lease Commitments 2018	49
Net Lease Commitments 2019	45
Net Lease Commitments Thereafter (to 2030)	90
Total Net Lease Commitments	$338

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended
	Feb. 28, 2011	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2008	Jan. 27, 2011	Jul. 23, 2010
		litigation_cases
Contingencies And Commitments [Line Items]	'	'	'	'	'	'	'
Rental expense, net of sublease income	'	$49,000,000	$54,000,000	$50,000,000	'	'	'
Order Routing Litigation Cases Total (in number of cases)	'	5	'	'	'	'	'
Order Routing Litigation Cases Nebraska (in number of cases)	'	4	'	'	'	'	'
Yield Plus Fund's stated objective to maintain a per share net asset value	'	'	'	'	$1	'	'
Approximate percentage of the Yield Plus Fund assets which have been distributed	'	'	'	'	'	'	94.80%
Approximate remaining total assets in Yield Plus Fund	'	'	'	'	'	'	39,700,000
Approximate percentage of Yield Plus Fund held by TD Ameritrade, Inc. clients	'	79.00%	'	'	'	'	'
Per share amount payable to all eligible clients that purchased shares of the yield plus fund and continued to own those shares	'	'	'	'	'	$0.01	'
Amount paid to clients under the SEC yield plus fund settlement agreement	10,000,000	'	'	'	'	'	'
Company's estimate of its clients current aggregate shortfall in the Yield Plus Fund	'	36,000,000	'	'	'	'	'
Contingent liability for guarantees to securities clearinghouses and exchanges	'	0	0	'	'	'	'
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	'	$30,000,000	'	'	'	'	'

Commitments_and_Contingencies_3

Commitments and Contingencies - Collateral Available, Loaned or Repledged (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Billions, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'	'
Client margin securities	$16.20	$12.50
Stock borrowings	1	1.2
Total collateral available	17.2	13.7
Collateral loaned	2.4	1.9
Collateral repledged	2.5	1.8
Total collateral loaned or repledged	$4.90	$3.70

Commitments_and_Contingencies_4

Commitments and Contingencies - Summary of Cash Deposited with and Securities Pledged to Clearinghouses (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]	'	'
Cash deposited and securities pledged	$285	$176
Cash [Member]	'	'
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]	'	'
Cash deposited and securities pledged	104	115
U.S. Government Debt Securities [Member]	'	'
Cash Deposited with and Securities Pledged to Clearinghouses [Line Items]	'	'
Cash deposited and securities pledged	$181	$61

Fair_Value_Disclosures_Fair_Va

Fair Value Disclosures - Fair Value Hierarchy for Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
In Millions, unless otherwise specified
Assets	'	'	'	'
Cash equivalents	$1,460	$1,062	$915	$1,032
Investments segregated for regulatory purposes	5,116	5,894	'	'
Securities owned	332	323	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	595	596	'	'
Fair Value, Measurements, Recurring [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	332	323	'	'
Other assets	37	69	'	'
Total assets at fair value	4,773	3,406	'	'
Liabilities	'	'	'	'
Total liabilities at fair value	30	'	'	'
Fair Value, Measurements, Recurring [Member] | Money Market Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Cash equivalents	1,284	969	'	'
Fair Value, Measurements, Recurring [Member] | U.S. Government Debt Securities [Member]	'	'	'	'
Assets	'	'	'	'
Investments segregated for regulatory purposes	3,120	2,045	'	'
Securities owned	326	313	'	'
Other assets	4	4	'	'
Fair Value, Measurements, Recurring [Member] | Money Market And Other Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	1	1	'	'
Fair Value, Measurements, Recurring [Member] | Other Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	5	4	'	'
Fair Value, Measurements, Recurring [Member] | Pay Variable Interest Rate Swap [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	32	52	'	'
Fair Value, Measurements, Recurring [Member] | Auction Rate Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	'	5	'	'
Other assets	1	'	'	'
Fair Value, Measurements, Recurring [Member] | Forward Starting Interest Rate Swap [Member]	'	'	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	29	'	'	'
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	'	13	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	1	13	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	2	1	'	'
Other assets	0	13	'	'
Total assets at fair value	1,286	983	'	'
Liabilities	'	'	'	'
Total liabilities at fair value	1	'	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Cash equivalents	1,284	969	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Government Debt Securities [Member]	'	'	'	'
Assets	'	'	'	'
Investments segregated for regulatory purposes	0	0	'	'
Securities owned	0	0	'	'
Other assets	0	0	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market And Other Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	0	0	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Other Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	2	1	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Pay Variable Interest Rate Swap [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	0	0	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Auction Rate Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	'	0	'	'
Other assets	0	'	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Forward Starting Interest Rate Swap [Member]	'	'	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	0	'	'	'
Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	'	13	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	1	13	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	329	316	'	'
Other assets	36	56	'	'
Total assets at fair value	3,485	2,417	'	'
Liabilities	'	'	'	'
Total liabilities at fair value	29	'	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Cash equivalents	0	0	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Government Debt Securities [Member]	'	'	'	'
Assets	'	'	'	'
Investments segregated for regulatory purposes	3,120	2,045	'	'
Securities owned	326	313	'	'
Other assets	4	4	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market And Other Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	0	0	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Other Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	3	3	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Pay Variable Interest Rate Swap [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	32	52	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Auction Rate Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	'	0	'	'
Other assets	0	'	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Forward Starting Interest Rate Swap [Member]	'	'	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	29	'	'	'
Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	'	0	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	0	0	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	1	6	'	'
Other assets	1	0	'	'
Total assets at fair value	2	6	'	'
Liabilities	'	'	'	'
Total liabilities at fair value	0	'	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Cash equivalents	0	0	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | U.S. Government Debt Securities [Member]	'	'	'	'
Assets	'	'	'	'
Investments segregated for regulatory purposes	0	0	'	'
Securities owned	0	0	'	'
Other assets	0	0	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Money Market And Other Mutual Funds [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	1	1	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Other Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	0	0	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Pay Variable Interest Rate Swap [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	0	0	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Auction Rate Securities [Member]	'	'	'	'
Assets	'	'	'	'
Securities owned	'	5	'	'
Other assets	1	'	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Forward Starting Interest Rate Swap [Member]	'	'	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	0	'	'	'
Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]	'	'	'	'
Assets	'	'	'	'
Other assets	'	0	'	'
Liabilities	'	'	'	'
Accounts payable and accrued liabilities	$0	$0	'	'

Fair_Value_Disclosures_Additio

Fair Value Disclosures - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'	'
Maximum range of cash and cash equivalents original maturity	'3 months	'
Reverse repurchase agreements generally have a maturity	'7 days	'
Aggregate estimated fair value of the Senior Notes	$1,081	$1,100
Debt Instrument [Line Items]	'	'
Long-term debt	1,101	1,052
2014 Notes and 2019 Notes [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term debt	1,032	1,052
Secured Loan [Member]	'	'
Debt Instrument [Line Items]	'	'
Long-term debt	$69	'

Offsetting_Assets_and_Liabilit2

Offsetting Assets and Liabilities - Effect of Rights of Setoff Associated with Company's Recognized Assets and Liabilities (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Assets	$2,220	$3,890
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	2,220	3,890
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	-69	-168
Gross Amounts of Collateral Received (Including Cash) Not Offset in the Consolidated Balance Sheet	-2,125	-3,690
Net Amounts of Recognized Assets Subject to Master Netting Arrangements	26	32
Gross Amounts of Recognized Liabilities	2,413	'
Gross Amounts Offset in the Consolidated Balance Sheet	0	'
Net Amounts Presented in the Consolidated Balance Sheet	2,413	'
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	-69	'
Gross Amounts of Collateral Pledged (Including Cash) Not Offset in the Consolidated Balance Sheet	-2,044	'
Net Amounts of Recognized Liabilities Subject to Master Netting Arrangements	300	'
Pay Variable Interest Rate Swap [Member] | Other Assets [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Assets	32	52
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	32	52
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	0	0
Gross Amounts of Collateral Received (Including Cash) Not Offset in the Consolidated Balance Sheet	-32	-52
Net Amounts of Recognized Assets Subject to Master Netting Arrangements	0	0
Forward Starting Interest Rate Swap [Member] | Accounts Payable and Accrued Liabilities [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Liabilities	29	'
Gross Amounts Offset in the Consolidated Balance Sheet	0	'
Net Amounts Presented in the Consolidated Balance Sheet	29	'
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	0	'
Gross Amounts of Collateral Pledged (Including Cash) Not Offset in the Consolidated Balance Sheet	-29	'
Net Amounts of Recognized Liabilities Subject to Master Netting Arrangements	0	'
Deposits Paid For Securities Borrowed [Member] | Receivable From Broker Dealer [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Assets	995	1,220
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	995	1,220
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	-69	-168
Gross Amounts of Collateral Received (Including Cash) Not Offset in the Consolidated Balance Sheet	-900	-1,020
Net Amounts of Recognized Assets Subject to Master Netting Arrangements	26	32
Deposits Received For Securities Loaned [Member] | Payable To Broker Dealer [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Liabilities	2,384	1,948
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	2,384	1,948
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	-69	-168
Gross Amounts of Collateral Pledged (Including Cash) Not Offset in the Consolidated Balance Sheet	-2,015	-1,561
Net Amounts of Recognized Liabilities Subject to Master Netting Arrangements	300	219
Reverse Repurchase Agreements [Member] | Investments Segregated For Regulatory Purposes [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross Amounts of Recognized Assets	1,193	2,618
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	1,193	2,618
Gross Amounts of Financial Instruments Not Offset in the Consolidated Balance Sheet	0	0
Gross Amounts of Collateral Received (Including Cash) Not Offset in the Consolidated Balance Sheet	-1,193	-2,618
Net Amounts of Recognized Assets Subject to Master Netting Arrangements	$0	$0

Offsetting_Assets_and_Liabilit3

Offsetting Assets and Liabilities - Effect of Rights of Setoff Associated with Company's Recognized Assets and Liabilities (Parenthetical) (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Offsetting Assets And Liabilities [Line Items]	'	'
Gross amounts of deposits paid for securities borrowed	$995	$1,220
Gross amounts of deposits received for securities loaned	2,384	1,948
Fair value of collateral the Company has received under enforceable master agreements, limited for table presentation purposes to the net amount of the recognized assets due from each counterparty	2,231	3,919
Fair value of collateral the Company has pledged under enforceable master agreements, limited for table presentation purposes to the net amount of the recognized liabilities due to each counterparty	2,124	1,721
Transacted Through The Option Clearing Corporation [Member]	'	'
Offsetting Assets And Liabilities [Line Items]	'	'
Gross amounts of deposits paid for securities borrowed	616	702
Gross amounts of deposits received for securities loaned	$754	$275

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) Net Change (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Available-for-sale Securities [Abstract]	'	'	'
Net unrealized gain	$0	$21	$28
Net unrealized gain, tax effect	0	-8	-10
Net unrealized gain, net of tax	0	13	18
Reclassification adjustment for net realized gain included in net income	0	-52	0
Reclassification adjustment for net realized gain included in net income, tax effect	0	19	0
Reclassification adjustment for net realized gain included in net income, net of tax	0	-33	0
Reclassification of impairment charge	0	3	0
Reclassification of impairment charge, tax effect	0	-1	0
Reclassification of impairment charge, net of tax	0	2	0
Change in unrealized gain on investments available-for-sale	0	-28	28
Change in unrealized gain on investments available-for-sale, tax effect	0	10	-10
Change in unrealized gain on investments available-for-sale, net of tax	0	-18	18
Cash Flow Hedging Instruments [Abstract]	'	'	'
Net unrealized loss	-29	0	0
Net unrealized loss, tax effect	11	0	0
Net unrealized loss, net of tax	-18	0	0
Total other comprehensive income (loss), before tax	-29	-28	28
Income tax effect	11	10	-10
Total other comprehensive income (loss), net of tax	($18)	($18)	$18

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Income (Loss) Balance Rollforward (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) Balance Rollforward [Line Items]	'	'	'
Beginning balance	$0	$18	$0
Other comprehensive income (loss), before reclassifications	-18	13	18
Amounts reclassified from accumulated other comprehensive income (loss)	0	-31	0
Total other comprehensive income (loss), net of tax	-18	-18	18
Ending balance	-18	0	18
Investments Available For Sale [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) Balance Rollforward [Line Items]	'	'	'
Beginning balance	0	18	0
Other comprehensive income (loss), before reclassifications	0	13	18
Amounts reclassified from accumulated other comprehensive income (loss)	0	-31	0
Total other comprehensive income (loss), net of tax	0	-18	18
Ending balance	0	0	18
Forward Starting Interest Rate Swap [Member]	'	'	'
Accumulated Other Comprehensive Income (Loss) Balance Rollforward [Line Items]	'	'	'
Beginning balance	0	0	0
Other comprehensive income (loss), before reclassifications	-18	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	0
Total other comprehensive income (loss), net of tax	-18	0	0
Ending balance	($18)	$0	$0

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
	board_of_directors_member
Related Party Transaction [Line Items]	'	'
Toronto-Dominion Bank percentage of ownership in the Company	41.00%	'
Toronto-Dominion Bank's right to designate to the Company's board of directors	5	'
Board of Directors Total Members	12	'
Adjustments required to adjust variable rate leg of interest rate swaps under current IDA Agreement	'1 month	'
Contingent liability carried on the consolidated balance sheets for the Insured Deposit Account Agreement	$0	$0
Insured Deposit Account Agreement Fee Example [Member]	'	'
Related Party Transaction [Line Items]	'	'
Amount of deposits, in the insured deposit account agreement fee example	100,000,000	'
Term of deposits invested in fixed rate investments, in the insured deposit account agreement fee example	'5 years	'
Term of fixed rate investments that deposits are invested in, in the insured deposit account agreement fee example	'5 years	'
Fixed yield for applicable LIBOR-based swaps, in the insured deposit account agreement fee example	1.45%	'
Gross fixed yield earned on deposits, in the insured deposit account agreement fee example	1.45%	'
New IDA Agreement [Member]	'	'
Related Party Transaction [Line Items]	'	'
Agreement effective date	1-Jan-13	'
Agreement expiration date	1-Jul-18	'
Agreement successive renewal terms	'5 years	'
Prior written notice period for termination of agreement by any party	'2 years	'
Number Of Primary Components Of Fee Earned On Ida Agreement	2	'
Percentage of fixed rate notional investments	75.00%	'
Percentage of floating rate investments	25.00%	'
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	'
New IDA Agreement [Member] | Maximum [Member]	'	'
Related Party Transaction [Line Items]	'	'
Servicing fee percentage (in basis points)	0.25%	'
Short-term fixed-rate notional investments maturity	'24 months	'
New IDA Agreement [Member] | Minimum [Member]	'	'
Related Party Transaction [Line Items]	'	'
Servicing fee percentage (in basis points)	0.03%	'
New IDA Agreement [Member] | New Fixed Rate Notional Investments [Member]	'	'
Related Party Transaction [Line Items]	'	'
Event 1 Federal Funds effective rate minimum	0.75%	'
Term Of US Dollar Interest Rate Swaps	'5 years	'
Event 2 Minimum Rate on five-year U.S. dollar interest rate swaps for 20 consecutive business days	1.50%	'
Event 2 number of consecutive business days required above the minimum rate on U.S. dollar interest rate swaps for reduction in rate earned by Company in the case of Event 1 and Event 2	'20 days	'
The percentage used in the calculation to reduce the rate earned by the Company on new fixed-rate notional investments in the case of event 1 and event 2	20.00%	'
Maximum reduction to rate earned by Company in the case of event 1 and event 2	0.10%	'

Related_Party_Transactions_Sum

Related Party Transactions - Summary of Revenues Resulting from Transactions with Related Parties (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]	'	'	'
Revenues from TD and Affiliates	$837	$821	$844
Insured Deposit Account Fees [Member] | Insured Deposit Account Agreement [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Revenues from TD and Affiliates	820	804	828
Various [Member] | Referral and Strategic Alliance Agreement [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Revenues from TD and Affiliates	12	11	8
Various [Member] | Other [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Revenues from TD and Affiliates	$5	$6	$8

Related_Party_Transactions_Sum1

Related Party Transactions - Summary of Expenses Resulting from Transactions with Related Parties (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]	'	'	'
Expenses to TD and Affiliates	$20	$23	$22
Professional Services [Member] | Canadian Call Center Services Agreement [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Expenses to TD and Affiliates	17	19	18
Various [Member] | Other [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Expenses to TD and Affiliates	$3	$4	$4

Related_Party_Transactions_Sum2

Related Party Transactions - Summary of Classification and Amount of Receivables from and Payables to Affiliates of Company (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Assets:	'	'
Receivable from brokers, dealers and clearing organizations	$1,108	$1,348
Receivable from affiliates	99	117
Liabilities:	'	'
Payable to brokers, dealers and clearing organizations	2,421	1,973
Payable to affiliates	5	4
Related Party Assets [Member]	'	'
Assets:	'	'
Receivable from brokers, dealers and clearing organizations	1	1
Receivable from affiliates	99	117
Related Party Liabilities [Member]	'	'
Liabilities:	'	'
Payable to brokers, dealers and clearing organizations	96	115
Payable to affiliates	$5	$4

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Balance Sheet (Detail) (USD $)	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
ASSETS	'	'	'	'
Cash and cash equivalents	$1,460,000,000	$1,062,000,000	$915,000,000	$1,032,000,000
Cash and investments segregated and on deposit for regulatory purposes	5,116,000,000	5,894,000,000	'	'
Receivable from brokers, dealers and clearing organizations	1,108,000,000	1,348,000,000	'	'
Receivable from clients, net	11,639,000,000	8,984,000,000	'	'
Investments in subsidiaries	0	0	'	'
Receivable from affiliates	99,000,000	117,000,000	'	'
Goodwill	2,467,000,000	2,467,000,000	'	'
Acquired intangible assets, net	751,000,000	841,000,000	'	'
Other, net	1,191,000,000	1,123,000,000	'	'
Total assets	23,831,000,000	21,836,000,000	'	'
Liabilities:	'	'	'	'
Payable to brokers, dealers and clearing organizations	2,421,000,000	1,973,000,000	'	'
Payable to clients	14,497,000,000	13,183,000,000	'	'
Accounts payable and accrued liabilities	595,000,000	596,000,000	'	'
Payable to affiliates	5,000,000	4,000,000	'	'
Notes payable	150,000,000	0	'	'
Long-term debt	1,101,000,000	1,052,000,000	'	'
Deferred income taxes	314,000,000	352,000,000	'	'
Total liabilities	19,083,000,000	17,160,000,000	'	'
Stockholders' equity	4,748,000,000	4,676,000,000	4,425,000,000	4,116,000,000
Total liabilities and stockholders' equity	23,831,000,000	21,836,000,000	'	'
TD Ameritrade Holding Corporation [Member]	'	'	'	'
ASSETS	'	'	'	'
Cash and cash equivalents	117,000,000	199,000,000	178,000,000	94,000,000
Cash and investments segregated and on deposit for regulatory purposes	0	0	'	'
Receivable from brokers, dealers and clearing organizations	0	0	'	'
Receivable from clients, net	0	0	'	'
Investments in subsidiaries	5,868,000,000	5,568,000,000	'	'
Receivable from affiliates	11,000,000	4,000,000	'	'
Goodwill	0	0	'	'
Acquired intangible assets, net	0	0	'	'
Other, net	156,000,000	140,000,000	'	'
Total assets	6,152,000,000	5,911,000,000	'	'
Liabilities:	'	'	'	'
Payable to brokers, dealers and clearing organizations	0	0	'	'
Payable to clients	0	0	'	'
Accounts payable and accrued liabilities	153,000,000	180,000,000	'	'
Payable to affiliates	0	3,000,000	'	'
Notes payable	150,000,000	'	'	'
Long-term debt	1,101,000,000	1,052,000,000	'	'
Deferred income taxes	0	0	'	'
Total liabilities	1,404,000,000	1,235,000,000	'	'
Stockholders' equity	4,748,000,000	4,676,000,000	'	'
Total liabilities and stockholders' equity	6,152,000,000	5,911,000,000	'	'
Guarantor Subsidiary [Member]	'	'	'	'
ASSETS	'	'	'	'
Cash and cash equivalents	2,000,000	7,000,000	6,000,000	7,000,000
Cash and investments segregated and on deposit for regulatory purposes	0	0	'	'
Receivable from brokers, dealers and clearing organizations	0	0	'	'
Receivable from clients, net	0	0	'	'
Investments in subsidiaries	5,754,000,000	5,360,000,000	'	'
Receivable from affiliates	2,000,000	3,000,000	'	'
Goodwill	0	0	'	'
Acquired intangible assets, net	146,000,000	146,000,000	'	'
Other, net	16,000,000	9,000,000	'	'
Total assets	5,920,000,000	5,525,000,000	'	'
Liabilities:	'	'	'	'
Payable to brokers, dealers and clearing organizations	0	0	'	'
Payable to clients	0	0	'	'
Accounts payable and accrued liabilities	0	0	'	'
Payable to affiliates	0	0	'	'
Notes payable	0	'	'	'
Long-term debt	0	0	'	'
Deferred income taxes	52,000,000	51,000,000	'	'
Total liabilities	52,000,000	51,000,000	'	'
Stockholders' equity	5,868,000,000	5,474,000,000	'	'
Total liabilities and stockholders' equity	5,920,000,000	5,525,000,000	'	'
Non-Guarantor Subsidiaries [Member]	'	'	'	'
ASSETS	'	'	'	'
Cash and cash equivalents	1,341,000,000	856,000,000	731,000,000	931,000,000
Cash and investments segregated and on deposit for regulatory purposes	5,116,000,000	5,894,000,000	'	'
Receivable from brokers, dealers and clearing organizations	1,108,000,000	1,348,000,000	'	'
Receivable from clients, net	11,639,000,000	8,984,000,000	'	'
Investments in subsidiaries	0	550,000,000	'	'
Receivable from affiliates	97,000,000	117,000,000	'	'
Goodwill	2,467,000,000	2,467,000,000	'	'
Acquired intangible assets, net	605,000,000	695,000,000	'	'
Other, net	1,073,000,000	1,015,000,000	'	'
Total assets	23,446,000,000	21,926,000,000	'	'
Liabilities:	'	'	'	'
Payable to brokers, dealers and clearing organizations	2,421,000,000	1,973,000,000	'	'
Payable to clients	14,497,000,000	13,183,000,000	'	'
Accounts payable and accrued liabilities	455,000,000	424,000,000	'	'
Payable to affiliates	16,000,000	8,000,000	'	'
Notes payable	0	'	'	'
Long-term debt	0	0	'	'
Deferred income taxes	303,000,000	334,000,000	'	'
Total liabilities	17,692,000,000	15,922,000,000	'	'
Stockholders' equity	5,754,000,000	6,004,000,000	'	'
Total liabilities and stockholders' equity	23,446,000,000	21,926,000,000	'	'
Eliminations [Member]	'	'	'	'
ASSETS	'	'	'	'
Cash and cash equivalents	0	0	'	'
Cash and investments segregated and on deposit for regulatory purposes	0	0	'	'
Receivable from brokers, dealers and clearing organizations	0	0	'	'
Receivable from clients, net	0	0	'	'
Investments in subsidiaries	-11,622,000,000	-11,478,000,000	'	'
Receivable from affiliates	-11,000,000	-7,000,000	'	'
Goodwill	0	0	'	'
Acquired intangible assets, net	0	0	'	'
Other, net	-54,000,000	-41,000,000	'	'
Total assets	-11,687,000,000	-11,526,000,000	'	'
Liabilities:	'	'	'	'
Payable to brokers, dealers and clearing organizations	0	0	'	'
Payable to clients	0	0	'	'
Accounts payable and accrued liabilities	-13,000,000	-8,000,000	'	'
Payable to affiliates	-11,000,000	-7,000,000	'	'
Notes payable	0	'	'	'
Long-term debt	0	0	'	'
Deferred income taxes	-41,000,000	-33,000,000	'	'
Total liabilities	-65,000,000	-48,000,000	'	'
Stockholders' equity	-11,622,000,000	-11,478,000,000	'	'
Total liabilities and stockholders' equity	($11,687,000,000)	($11,526,000,000)	'	'

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Income (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	$795	$763	$812	$752	$709	$725	$679	$651	$3,123	$2,764	$2,641
Operating expenses	'	'	'	'	'	'	'	'	1,838	1,708	1,707
Operating income	338	316	323	307	279	298	237	241	1,285	1,056	934
Other expense (income)	'	'	'	'	'	'	'	'	15	-32	28
Income (loss) before income taxes and equity in income of subsidiaries	'	'	'	'	'	'	'	'	1,270	1,088	906
Provision for (benefit from) income taxes	'	'	'	'	'	'	'	'	483	413	320
Income (loss) before equity in income of subsidiaries	'	'	'	'	'	'	'	'	787	675	586
Equity in income of subsidiaries	'	'	'	'	'	'	'	'	0	0	0
Net income	211	190	194	192	200	184	144	147	787	675	586
TD Ameritrade Holding Corporation [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	'	'	'	'	'	'	'	'	14	12	32
Operating expenses	'	'	'	'	'	'	'	'	13	10	28
Operating income	'	'	'	'	'	'	'	'	1	2	4
Other expense (income)	'	'	'	'	'	'	'	'	24	-23	29
Income (loss) before income taxes and equity in income of subsidiaries	'	'	'	'	'	'	'	'	-23	25	-25
Provision for (benefit from) income taxes	'	'	'	'	'	'	'	'	-14	8	-19
Income (loss) before equity in income of subsidiaries	'	'	'	'	'	'	'	'	-9	17	-6
Equity in income of subsidiaries	'	'	'	'	'	'	'	'	796	658	592
Net income	'	'	'	'	'	'	'	'	787	675	586
Guarantor Subsidiary [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	'	'	'	'	'	'	'	'	0	0	0
Operating expenses	'	'	'	'	'	'	'	'	0	0	0
Operating income	'	'	'	'	'	'	'	'	0	0	0
Other expense (income)	'	'	'	'	'	'	'	'	0	0	0
Income (loss) before income taxes and equity in income of subsidiaries	'	'	'	'	'	'	'	'	0	0	0
Provision for (benefit from) income taxes	'	'	'	'	'	'	'	'	-1	0	-3
Income (loss) before equity in income of subsidiaries	'	'	'	'	'	'	'	'	1	0	3
Equity in income of subsidiaries	'	'	'	'	'	'	'	'	787	634	577
Net income	'	'	'	'	'	'	'	'	788	634	580
Non-Guarantor Subsidiaries [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	'	'	'	'	'	'	'	'	3,123	2,763	2,641
Operating expenses	'	'	'	'	'	'	'	'	1,839	1,709	1,711
Operating income	'	'	'	'	'	'	'	'	1,284	1,054	930
Other expense (income)	'	'	'	'	'	'	'	'	-9	-9	-1
Income (loss) before income taxes and equity in income of subsidiaries	'	'	'	'	'	'	'	'	1,293	1,063	931
Provision for (benefit from) income taxes	'	'	'	'	'	'	'	'	498	405	342
Income (loss) before equity in income of subsidiaries	'	'	'	'	'	'	'	'	795	658	589
Equity in income of subsidiaries	'	'	'	'	'	'	'	'	17	36	33
Net income	'	'	'	'	'	'	'	'	812	694	622
Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Condensed Income Statements, Captions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	'	'	'	'	'	'	'	'	-14	-11	-32
Operating expenses	'	'	'	'	'	'	'	'	-14	-11	-32
Operating income	'	'	'	'	'	'	'	'	0	0	0
Other expense (income)	'	'	'	'	'	'	'	'	0	0	0
Income (loss) before income taxes and equity in income of subsidiaries	'	'	'	'	'	'	'	'	0	0	0
Provision for (benefit from) income taxes	'	'	'	'	'	'	'	'	0	0	0
Income (loss) before equity in income of subsidiaries	'	'	'	'	'	'	'	'	0	0	0
Equity in income of subsidiaries	'	'	'	'	'	'	'	'	-1,600	-1,328	-1,202
Net income	'	'	'	'	'	'	'	'	($1,600)	($1,328)	($1,202)

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information - Schedule of Condensed Consolidating Statement of Cash Flows (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Net cash provided by (used in) operating activities	$1,025	$739	$592
Cash flows from investing activities:	'	'	'
Purchase of property and equipment	-144	-144	-186
Proceeds from sale and maturity of short-term investments	4	154	4
Purchase of short-term investments	-4	-4	-155
Purchase of investments	0	0	-44
Proceeds from sale of investments	25	88	2
Other, net	2	2	2
Net cash provided by (used in) investing activities	-117	96	-377
Cash flows from financing activities:	'	'	'
Proceeds from issuance of long-term debt	69	0	0
Principal payments on long-term debt	0	-250	0
Proceeds from notes payable	230	275	0
Principal payments on notes payable	-80	-275	0
Payment of cash dividends	-540	-471	-132
Purchase of treasury stock	-207	-5	-208
Other, net	18	38	8
Net cash used in financing activities	-510	-688	-332
Intercompany investing and financing activities, net	0	0	0
Net increase (decrease) in cash and cash equivalents	398	147	-117
Cash and cash equivalents at beginning of year	1,062	915	1,032
Cash and cash equivalents at end of year	1,460	1,062	915
TD Ameritrade Holding Corporation [Member]	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Net cash provided by (used in) operating activities	-81	-70	46
Cash flows from investing activities:	'	'	'
Purchase of property and equipment	0	0	0
Proceeds from sale and maturity of short-term investments	0	150	0
Purchase of short-term investments	0	0	-152
Purchase of investments	'	'	-43
Proceeds from sale of investments	13	78	2
Other, net	0	0	0
Net cash provided by (used in) investing activities	13	228	-193
Cash flows from financing activities:	'	'	'
Proceeds from issuance of long-term debt	69	'	'
Principal payments on long-term debt	'	-250	'
Proceeds from notes payable	230	275	'
Principal payments on notes payable	-80	-275	'
Payment of cash dividends	-540	-471	-132
Purchase of treasury stock	-207	-5	-208
Other, net	18	43	4
Net cash used in financing activities	-510	-683	-336
Intercompany investing and financing activities, net	496	546	567
Net increase (decrease) in cash and cash equivalents	-82	21	84
Cash and cash equivalents at beginning of year	199	178	94
Cash and cash equivalents at end of year	117	199	178
Guarantor Subsidiary [Member]	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Net cash provided by (used in) operating activities	1	1	2
Cash flows from investing activities:	'	'	'
Purchase of property and equipment	0	0	0
Proceeds from sale and maturity of short-term investments	0	0	0
Purchase of short-term investments	0	0	0
Purchase of investments	'	'	0
Proceeds from sale of investments	0	0	0
Other, net	0	0	0
Net cash provided by (used in) investing activities	0	0	0
Cash flows from financing activities:	'	'	'
Proceeds from issuance of long-term debt	0	'	'
Principal payments on long-term debt	'	0	'
Proceeds from notes payable	0	0	'
Principal payments on notes payable	0	0	'
Payment of cash dividends	0	0	0
Purchase of treasury stock	0	0	0
Other, net	0	0	0
Net cash used in financing activities	0	0	0
Intercompany investing and financing activities, net	-6	0	-3
Net increase (decrease) in cash and cash equivalents	-5	1	-1
Cash and cash equivalents at beginning of year	7	6	7
Cash and cash equivalents at end of year	2	7	6
Non-Guarantor Subsidiaries [Member]	'	'	'
Condensed Cash Flow Statements, Captions [Line Items]	'	'	'
Net cash provided by (used in) operating activities	1,105	808	544
Cash flows from investing activities:	'	'	'
Purchase of property and equipment	-144	-144	-186
Proceeds from sale and maturity of short-term investments	4	4	4
Purchase of short-term investments	-4	-4	-3
Purchase of investments	'	'	-1
Proceeds from sale of investments	12	10	0
Other, net	2	2	2
Net cash provided by (used in) investing activities	-130	-132	-184
Cash flows from financing activities:	'	'	'
Proceeds from issuance of long-term debt	0	'	'
Principal payments on long-term debt	'	0	'
Proceeds from notes payable	0	0	'
Principal payments on notes payable	0	0	'
Payment of cash dividends	0	0	0
Purchase of treasury stock	0	0	0
Other, net	0	-5	4
Net cash used in financing activities	0	-5	4
Intercompany investing and financing activities, net	-490	-546	-564
Net increase (decrease) in cash and cash equivalents	485	125	-200
Cash and cash equivalents at beginning of year	856	731	931
Cash and cash equivalents at end of year	$1,341	$856	$731

Quarterly_Data_Schedule_of_Qua

Quarterly Data - Schedule of Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Quarterly Financial Information Disclosure [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net revenues	$795	$763	$812	$752	$709	$725	$679	$651	$3,123	$2,764	$2,641
Operating income	338	316	323	307	279	298	237	241	1,285	1,056	934
Net income	$211	$190	$194	$192	$200	$184	$144	$147	$787	$675	$586
Basic earnings per share (in dollars per share)	$0.39	$0.34	$0.35	$0.35	$0.36	$0.33	$0.26	$0.27	$1.43	$1.23	$1.07
Diluted earnings per share (in dollars per share)	$0.38	$0.34	$0.35	$0.35	$0.36	$0.33	$0.26	$0.27	$1.42	$1.22	$1.06

Quarterly_Data_Schedule_of_Qua1

Quarterly Data - Schedule of Quarterly Financial Data (Parenthetical) (Detail) (Knight-GETCO Merger Impact [Member], USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013
Knight-GETCO Merger Impact [Member]	'
Interim Reporting [Line Items]	'
Pre-tax gain in connection with Knight-GETCO merger	$54
After tax gain in connection with Knight-GETCO merger	$34
Per diluted share impact of the after tax gain in connection with Knight-GETCO merger	$0.06