Discover Financial Services (DFS) 10-Q 28 Apr 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 22, 2016
Document Information [Line Items]
Document type	10-Q
Amendment flag	false
Document period end date	Mar. 31, 2016
Document fiscal year focus	2,016
Document fiscal period focus	Q1
Entity registrant name	Discover Financial Services
Entity central index key	1,393,612
Current fiscal year end date	--12-31
Entity filer category	Large Accelerated Filer
Entity common stock, shares outstanding		412,225,311

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 12,135	$ 9,572
Restricted cash	1,010	99
Investment securities (includes $2,824 and $2,963 at fair value at March 31, 2016 and December 31, 2015, respectively)	2,956	3,084
Loan receivables
Loan receivables	70,320	72,385
Allowance for loan losses	(1,921)	(1,869)
Net loan receivables	68,399	70,516
Premises and equipment, net	706	693
Goodwill	255	255
Intangible assets, net	167	168
Other assets	2,465	2,412
Total assets	88,093	86,799
Deposits
Interest-bearing deposit accounts	48,055	47,094
Non-interest bearing deposit accounts	410	437
Total deposits	48,465	47,531
Long-term borrowings	24,752	24,650	[1]
Accrued expenses and other liabilities	3,560	3,343
Total liabilities	$ 76,777	$ 75,524
Commitments, contingencies and guarantees (Notes 9, 12 and 13)
Stockholders’ Equity:
Common stock, par value $0.01 per share; 2,000,000,000 shares authorized; 562,210,058 and 560,679,352 shares issued at March 31, 2016 and December 31, 2015, respectively	$ 5	$ 5
Preferred stock, par value $0.01 per share; 200,000,000 shares authorized; 575,000 shares issued and outstanding and aggregate liquidation preference of $575 at March 31, 2016 and December 31, 2015	560	560
Additional paid-in capital	3,913	3,885
Retained earnings	13,698	13,250
Accumulated other comprehensive loss	(172)	(160)
Treasury stock, at cost; 147,983,359 and 139,000,423 shares at March 31, 2016 and December 31, 2015, respectively	(6,688)	(6,265)
Total stockholders’ equity	11,316	11,275
Total liabilities and stockholders’ equity	88,093	86,799
Variable Interest Entity, Primary Beneficiary [Member]
Assets
Restricted cash	1,010	99
Loan receivables
Loan receivables	28,761	30,551
Allowance for loan losses	(811)	(811)
Other assets	6	5
Deposits
Long-term borrowings	16,779	16,735	[1]
Accrued expenses and other liabilities	$ 13	$ 12
[1]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($)		Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Amount of total investment securities at fair value (in dollars)	[1]	$ 2,824,000,000	$ 2,963,000,000
Common stock, par value per share (in dollars per share)		$ 0.01	$ 0.01
Common stock, shares authorized		2,000,000,000	2,000,000,000
Common stock, shares issued		562,210,058	560,679,352
Preferred stock, par or stated value per share (in dollars per share)		$ 0.01	$ 0.01
Preferred stock, shares authorized		200,000,000	200,000,000
Preferred stock, shares issued		575,000	575,000
Preferred stock, shares outstanding		575,000	575,000
Preferred stock, liquidation preference (in dollars)		$ 575,000,000	$ 575,000,000
Treasury stock, shares		147,983,359	139,000,423
[1]	Available-for-sale investment securities are reported at fair value.

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Interest income
Credit card loans	$ 1,733	$ 1,606
Other loans	326	304
Investment securities	11	13
Other interest income	14	6
Total interest income	2,084	1,929
Interest expense
Deposits	162	152
Short-term borrowings	0	1
Long-term borrowings	172	147
Total interest expense	334	300
Net interest income	1,750	1,629
Provision for loan losses	424	390
Net interest income after provision for loan losses	1,326	1,239
Other income
Discount and interchange revenue, net	273	268
Protection products revenue	61	71
Loan fee income	80	81
Transaction processing revenue	36	42
Gain on investments	0	8
Gain on origination and sale of mortgage loans	0	40
Other income	24	32
Total other income	474	542
Other expense
Employee compensation and benefits	345	331
Marketing and business development	162	182
Information processing and communications	88	88
Professional fees	160	127
Premises and equipment	24	24
Other expense	107	121
Total other expense	886	873
Income before income tax expense	914	908
Income tax expense	339	322
Net income	575	586
Net income allocated to common stockholders	$ 562	$ 573
Basic earnings per common share (in dollars per share)	$ 1.35	$ 1.28
Diluted earnings per common share (in dollars per share)	1.35	1.28
Dividends declared per common share (in dollars per share)	$ 0.28	$ 0.24

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income	$ 575	$ 586
Other comprehensive income (loss), net of taxes
Unrealized gain on available-for-sale investment securities, net of tax	14	0
Unrealized loss on cash flow hedges, net of tax	(26)	(23)
Other comprehensive loss	(12)	(23)
Comprehensive income	$ 563	$ 563

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Preferred stock, shares outstanding, balance at beginning of period (in shares) at Dec. 31, 2014		575,000
Stockholders' equity, balance at beginning of period at Dec. 31, 2014	$ 11,134	$ 560	$ 5	$ 3,790	$ 11,467	$ (138)	$ (4,550)
Common stock, shares outstanding, balance at beginning of period (in shares) at Dec. 31, 2014			558,194,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	586				586
Other comprehensive loss	(23)					(23)
Purchases of treasury stock	(420)						(420)
Common stock issued under employee benefit plans (in shares)			18,000
Common stock issued under employee benefit plans	1		$ 0	1
Common stock issued and stock-based compensation expense (in shares)			2,330,000
Common stock issued and stock-based compensation expense	50		$ 0	50
Dividends — common stock	(108)				(108)
Dividends — preferred stock	(9)				(9)
Preferred stock, shares outstanding, balance at end of period (in shares) at Mar. 31, 2015		575,000
Stockholders' equity, balance at end of period at Mar. 31, 2015	$ 11,211	$ 560	$ 5	3,841	11,936	(161)	(4,970)
Common stock, shares outstanding, balance at end of period (in shares) at Mar. 31, 2015			560,542,000
Preferred stock, shares outstanding, balance at beginning of period (in shares) at Dec. 31, 2015	575,000	575,000
Stockholders' equity, balance at beginning of period at Dec. 31, 2015	$ 11,275	$ 560	$ 5	3,885	13,250	(160)	(6,265)
Common stock, shares outstanding, balance at beginning of period (in shares) at Dec. 31, 2015			560,679,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	575				575
Other comprehensive loss	(12)					(12)
Purchases of treasury stock	(423)						(423)
Common stock issued under employee benefit plans (in shares)			21,000
Common stock issued under employee benefit plans	1		$ 0	1
Common stock issued and stock-based compensation expense (in shares)			1,510,000
Common stock issued and stock-based compensation expense	27		$ 0	27
Dividends — common stock	(118)				(118)
Dividends — preferred stock	$ (9)				(9)
Preferred stock, shares outstanding, balance at end of period (in shares) at Mar. 31, 2016	575,000	575,000
Stockholders' equity, balance at end of period at Mar. 31, 2016	$ 11,316	$ 560	$ 5	$ 3,913	$ 13,698	$ (172)	$ (6,688)
Common stock, shares outstanding, balance at end of period (in shares) at Mar. 31, 2016			562,210,000

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities
Net income	$ 575	$ 586
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	424	390
Depreciation and amortization	84	95
Amortization of deferred revenues and accretion of accretable yield on acquired loans	(98)	(113)
Net loss (gain) on origination and sale of loans, investments and other assets	13	(36)
Proceeds from sale of mortgage loans originated for sale	0	1,083
Net principal disbursed on mortgage loans originated for sale	0	(1,110)
Other, net	4	(8)
Changes in assets and liabilities:
Increase in other assets	(33)	(40)
Increase in accrued expenses and other liabilities	189	216
Net cash provided by operating activities	1,158	1,063
Cash flows from investing activities
Maturities and sales of available-for-sale investment securities	158	1,188
Maturities of held-to-maturity investment securities	5	2
Purchases of held-to-maturity investment securities	(16)	(17)
Net principal repaid on loans originated for investment	1,793	2,129
Purchases of other investments	(1)	(5)
Increase in restricted cash	(911)	(3)
Purchases of premises and equipment	(46)	(41)
Net cash provided by investing activities	982	3,253
Cash flows from financing activities
Net increase in short-term borrowings	0	53
Proceeds from issuance of securitized debt	991	950
Maturities and repayment of securitized debt	(980)	(1,083)
Proceeds from issuance of other long-term borrowings	38	499
Proceeds from issuance of common stock	1	1
Purchases of treasury stock	(423)	(420)
Net increase in deposits	925	333
Dividends paid on common and preferred stock	(129)	(119)
Net cash provided by financing activities	423	214
Net increase in cash and cash equivalents	2,563	4,530
Cash and cash equivalents, at beginning of period	9,572	7,284
Cash and cash equivalents, at end of period	$ 12,135	$ 11,814

Background and Basis of Present

Background and Basis of Presentation	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	Background and Basis of Presentation Description of Business Discover Financial Services (“DFS” or the “Company”) is a direct banking and payment services company. The Company is a bank holding company under the Bank Holding Company Act of 1956 as well as a financial holding company under the Gramm-Leach-Bliley Act and therefore is subject to oversight, regulation and examination by the Board of Governors of the Federal Reserve System (the “Federal Reserve”). The Company provides direct banking products and services and payment services through its subsidiaries. The Company offers its customers credit card loans, private student loans, personal loans, home equity loans and deposit products. The Company also operates the Discover Network, the PULSE network (“PULSE”) and Diners Club International (“Diners Club”). The Discover Network processes transactions for Discover-branded credit cards and provides payment transaction processing and settlement services. PULSE operates an electronic funds transfer network, providing financial institutions issuing debit cards on the PULSE network with access to ATMs domestically and internationally, as well as point-of-sale terminals at retail locations throughout the U.S. for debit card transactions. Diners Club is a global payments network of licensees, which are generally financial institutions, that issue Diners Club branded charge cards and/or provide card acceptance services. The Company’s business segments are Direct Banking and Payment Services. The Direct Banking segment includes Discover-branded credit cards issued to individuals on the Discover Network and other consumer products and services, including private student loans, personal loans, home equity loans, and other consumer lending and deposit products. The majority of Direct Banking revenues relate to interest income earned on the segment's loan products. Additionally, the Company's credit card products generate substantially all revenues related to discount and interchange, protection products and loan fee income. The Payment Services segment includes PULSE, an automated teller machine, debit and electronic funds transfer network; Diners Club, a global payments network; and the Company’s Network Partners business, which provides payment transaction processing and settlement services on the Discover Network. The majority of Payment Services revenues relate to transaction processing revenue from PULSE and royalty and licensee revenue (included in other income) from Diners Club. Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management, the financial statements reflect all adjustments which are necessary for a fair presentation of the results for the interim period. All such adjustments are of a normal, recurring nature. The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and related disclosures. These estimates are based on information available as of the date of the condensed consolidated financial statements. The Company believes that the estimates used in the preparation of the condensed consolidated financial statements are reasonable. Actual results could differ from these estimates. These interim condensed consolidated financial statements should be read in conjunction with the Company’s 2015 audited consolidated financial statements filed with the Company’s annual report on Form 10-K for the year ended December 31, 2015 . Change in Accounting Principle In April 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2015-03, Interest—-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which makes the presentation of debt issuance costs consistent with that of debt discounts and premiums. This ASU requires that debt issuance costs related to a recognized liability be presented in the balance sheet as a direct deduction from the carrying amount of that liability. Before becoming effective for the Company on January 1, 2016, these costs were recorded as deferred charges presented in other assets on the consolidated statements of financial condition. The guidance requires retrospective application in the financial statements. As such, some balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of a related liability. The impact of adopting this ASU was a reduction of other assets of $137 million , a reduction of long-term borrowings of $74 million and a reduction of deposits of $63 million at December 31, 2015. There was no impact to the consolidated statements of income. Recently Issued Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. This ASU requires excess tax benefits and tax deficiencies, which arise due to differences between the measure of compensation expense and the amount deductible for tax purposes, to be recorded directly through the income statement as a component of income tax expense. Under current GAAP, these differences are generally recorded in additional paid-in capital and thus have no impact on net income today. The change in treatment of excess tax benefits and tax deficiencies will also impact the computation of diluted earnings per share, and the cash flows associated with those items will be classified as operating activities on the statement of cash flows. The ASU will permit certain elective changes associated with stock compensation accounting. For example, companies can elect to account for forfeitures of awards as they occur rather than projecting forfeitures in the accrual of compensation expense. In addition, the ASU increases the proportion of shares an employer is permitted (though not required) to withhold on behalf of an employee to satisfy the employee’s income tax burden on a share-based award without causing the award to become subject to liability accounting. This ASU will become effective for the Company on January 1, 2017 and management is in the process of evaluating its impact. Upon adoption, the cumulative amounts associated with previous excess tax benefits will be reclassified from additional paid-in capital to retained earnings. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net). The guidance in this ASU provides clarification on the principal versus agent concept in relation to revenue recognition guidance issued as part of ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Topic 606 requires a company to determine whether it is a principal or an agent in a transaction in which another party is involved in providing goods or services to a customer by evaluating the nature of its promise to the customer. ASU 2016-08 provides clarification for identifying the good, service or right being transferred in a revenue transaction and identifies the principal as the party that controls the good, service or right prior to its transfer to the customer. The ASU provides further clarity on how to evaluate control in this context. This guidance will become effective for the Company on January 1, 2018 and management is evaluating the impact of these changes as part of its overall evaluation of ASU 2014-09. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The guidance will require lessees to capitalize most leases on their balance sheet whereas under current GAAP only capital leases are recognized on the lessee’s balance sheet. Leases which today are identified as capital leases will generally be identified as financing leases under the new guidance but otherwise their accounting treatment will remain relatively unchanged. Leases identified today as operating leases will generally remain in that category under the new standard, but both a right-of-use asset and a liability for remaining lease payments will now be required to be recognized on the balance sheet for this type of lease. The manner in which expenses associated with all leases are reported on the income statement will remain mostly unchanged. Lessor accounting also remains substantially unchanged by the new standard. The new guidance will become effective for the Company on January 1, 2019 and management is in the process of evaluating its impact. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The ASU will have limited impact on the Company since it does not change the guidance for classifying and measuring investments in debt securities or loans. The standard requires entities to measure certain cost-method equity investments at fair value with changes in value recognized in net income. Equity investments that do not have readily determinable fair values will be carried at cost, less any impairment, plus or minus changes resulting from any observable price changes in orderly transactions for an identical or similar investment of the same issuer. This ASU requires public entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans) on the balance sheet or the accompanying notes to the financial statements. This ASU will become effective for the Company on January 1, 2018 and is not expected to have a material impact to the financial statements. In April 2015, the FASB issued ASU No. 2015-05, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement. This ASU addresses whether a cloud computing arrangement contains a software license. Under this ASU a cloud computing arrangement contains a software license if the customer has the contractual right to take possession of the software at any time during the hosting period without significant penalty and provided it is feasible for the customer to either host the software internally or with an external party unrelated to the original vendor. Upon meeting both of these criteria, a customer should account for the software license within a cloud computing arrangement in a manner consistent with the acquisition of other software licenses. This could potentially change the timing of expense recognition associated with the contract. If a cloud computing arrangement does not meet both criteria, a customer will account for the arrangement entirely as a service contract. This ASU became effective for the Company on January 1, 2016. Management determined there were no existing contractual arrangements impacted by this ASU. The new guidance will be applied to any new contractual arrangements that meet the criteria discussed above. In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis. The guidance in this ASU was issued to improve targeted areas of the accounting rules for consolidation. This ASU changes the analysis companies will use to determine if certain types of legal entities should be consolidated. In addition, it modifies the determination of whether a limited liability entity should be evaluated as a variable interest entity ("VIE") or a voting interest entity and eliminates the presumption that a general partner should consolidate a limited partnership. The new amendment became effective for the Company on January 1, 2016. The amendments primarily triggered a review of the Company’s tax credit investments, which typically utilize limited liability entities. As a result of that review, management determined that its prior conclusions associated with the Company's tax credit investments continue to be appropriate. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The guidance in this ASU supersedes existing revenue recognition requirements in Topic 605, Revenue Recognition, including an assortment of transaction-specific and industry-specific rules. This ASU establishes a principles-based model under which revenue from a contract is allocated to the distinct performance obligations within the contract and recognized in income as each performance obligation is satisfied. ASU Topic 606 does not apply to rights or obligations associated with financial instruments (for example, interest income from loans or investments, or interest expense on debt), and therefore the Company’s net interest income should not be affected. The Company’s revenue from discount and interchange, protection products, transaction processing and certain fees are within the scope of these rules. Throughout 2015, management followed the discussions of the FASB and its Transition Resource Group pertaining to credit card arrangements, loyalty programs, and transaction processing arrangements, and how the new revenue recognition rules should be interpreted for each. Based on those discussions, management is considering the comments made as part of those discussions in its ongoing evaluation of the new standard. Management expects to complete its evaluation of the impact of this amendment in 2016. The new revenue recognition model will become effective for the Company on January 1, 2018. Upon adoption in 2018, as appropriate, the Company will record an adjustment to retained earnings as of the beginning of the year of initial application, which can be either the earliest comparative period presented, with all periods presented under the new rules, or January 1, 2018, without restating prior periods presented. Management has not yet determined which transition reporting option it will apply.

Business Dispositions

Business Dispositions	3 Months Ended
	Mar. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Business Dispositions	Business Dispositions On June 16, 2015, the Company announced the closing of the mortgage origination business it acquired in 2012, which was part of its Direct Banking segment. The disposition represented the exiting of an ancillary business and did not have a major impact on the Company’s operations.

Investments

Investments	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The Company’s investment securities consist of the following (dollars in millions): March 31, December 31, U.S. Treasury securities (1) $ 1,181 $ 1,273 U.S. government agency securities 492 494 States and political subdivisions of states 5 7 Residential mortgage-backed securities - Agency (2) 1,278 1,310 Total investment securities $ 2,956 $ 3,084 (1) Includes $20 million and $7 million of U.S. Treasury securities pledged as swap collateral in lieu of cash as of March 31, 2016 and December 31, 2015 , respectively. (2) Consists of residential mortgage-backed securities issued by Fannie Mae, Freddie Mac and Ginnie Mae. The amortized cost, gross unrealized gains and losses, and fair value of available-for-sale and held-to-maturity investment securities are as follows (dollars in millions): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value At March 31, 2016 Available-for-Sale Investment Securities (1) U.S. Treasury securities $ 1,177 $ 3 $ — $ 1,180 U.S. government agency securities 491 1 — 492 Residential mortgage-backed securities - Agency 1,134 18 — 1,152 Total available-for-sale investment securities $ 2,802 $ 22 $ — $ 2,824 Held-to-Maturity Investment Securities (2) U.S. Treasury securities (3) $ 1 $ — $ — $ 1 States and political subdivisions of states 5 — — 5 Residential mortgage-backed securities - Agency (4) 126 3 — 129 Total held-to-maturity investment securities $ 132 $ 3 $ — $ 135 At December 31, 2015 Available-for-Sale Investment Securities (1) U.S. Treasury securities $ 1,277 $ 1 $ (6 ) $ 1,272 U.S. government agency securities 492 2 — 494 Residential mortgage-backed securities - Agency 1,195 6 (4 ) 1,197 Total available-for-sale investment securities $ 2,964 $ 9 $ (10 ) $ 2,963 Held-to-Maturity Investment Securities (2) U.S. Treasury securities (3) $ 1 $ — $ — $ 1 States and political subdivisions of states 7 — — 7 Residential mortgage-backed securities - Agency (4) 113 1 — 114 Total held-to-maturity investment securities $ 121 $ 1 $ — $ 122 (1) Available-for-sale investment securities are reported at fair value. (2) Held-to-maturity investment securities are reported at amortized cost. (3) Amount represents securities pledged as collateral to a government-related merchant for which transaction settlement occurs beyond the normal 24-hour period. (4) Amounts represent residential mortgage-backed securities that were classified as held-to-maturity as they were entered into as a part of the Company's community reinvestment initiatives. The following table provides information about investment securities with aggregate gross unrealized losses and the length of time that individual investment securities have been in a continuous unrealized loss position (dollars in millions): Number of Securities in a Loss Position Less than 12 months More than 12 months Fair Value Unrealized Losses Fair Value Unrealized Losses At December 31, 2015 Available-for-Sale Investment Securities U.S. Treasury securities 1 $ 670 $ (6 ) $ — $ — Residential mortgage-backed securities - Agency 15 $ 486 $ (4 ) $ — $ — Aggregate gross unrealized losses were not material as of March 31, 2016 . There were no losses related to other-than-temporary impairments during the three months ended March 31, 2016 and 2015 . The following table provides information about proceeds from sales, recognized gains and losses and net unrealized gains and losses on available-for-sale securities (dollars in millions): For the Three Months Ended March 31, 2016 2015 Proceeds from the sales of available-for-sale investment securities $ — $ 899 Gain on sales of available-for-sale investment securities $ — $ 8 Net unrealized gain recorded in other comprehensive income, before-tax $ 23 $ — Net unrealized gain recorded in other comprehensive income, after-tax $ 14 $ — Maturities of available-for-sale debt securities and held-to-maturity debt securities are provided in the table below (dollars in millions): One Year or Less After One Year Through Five Years After Five Years Through Ten Years After Ten Years Total At March 31, 2016 Available-for-Sale Investment Securities—Amortized Cost U.S. Treasury securities $ 500 $ 677 $ — $ — $ 1,177 U.S. government agency securities 491 — — — 491 Residential mortgage-backed securities - Agency — — 359 775 1,134 Total available-for-sale investment securities $ 991 $ 677 $ 359 $ 775 $ 2,802 Held-to-Maturity Investment Securities—Amortized Cost U.S. Treasury securities $ 1 $ — $ — $ — $ 1 State and political subdivisions of states — — — 5 5 Residential mortgage-backed securities - Agency — — — 126 126 Total held-to-maturity investment securities $ 1 $ — $ — $ 131 $ 132 Available-for-Sale Investment Securities—Fair Values U.S. Treasury securities $ 501 $ 679 $ — $ — $ 1,180 U.S. government agency securities 492 — — — 492 Residential mortgage-backed securities - Agency — — 363 789 1,152 Total available-for-sale investment securities $ 993 $ 679 $ 363 $ 789 $ 2,824 Held-to-Maturity Investment Securities—Fair Values U.S. Treasury securities $ 1 $ — $ — $ — $ 1 State and political subdivisions of states — — — 5 5 Residential mortgage-backed securities - Agency — — — 129 129 Total held-to-maturity investment securities $ 1 $ — $ — $ 134 $ 135 Other Investments As a part of the Company's community reinvestment initiatives, the Company has made equity investments in certain limited partnerships and limited liability companies that finance the construction and rehabilitation of affordable rental housing, as well as stimulate economic development in low to moderate income communities. These investments are accounted for using the equity method of accounting and are recorded within other assets. The related commitment for future investments is recorded in accrued expenses and other liabilities within the condensed consolidated statements of financial condition. The portion of each investment's operating results allocable to the Company is recorded in other expense within the condensed consolidated statements of income. The Company earns a return primarily through the receipt of tax credits allocated to the affordable housing projects and the community revitalization projects. These investments are not consolidated as the Company does not have a controlling financial interest in the entities. As of March 31, 2016 and December 31, 2015 , the Company had outstanding investments in these entities of $315 million and $328 million , respectively, and related contingent liabilities of $56 million and $57 million , respectively. Of the above outstanding equity investments, the Company had $233 million and $238 million , respectively, of investments related to affordable housing projects, which had $56 million and $57 million related contingent liabilities as of March 31, 2016 and December 31, 2015 , respectively.

Loan Receivables

Loan Receivables	3 Months Ended
	Mar. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Loan Receivables	Loan Receivables The Company has three loan portfolio segments: credit card loans, other loans and purchased credit-impaired ("PCI") loans. The Company's classes of receivables within the three portfolio segments are depicted in the table below (dollars in millions): March 31, December 31, Loan receivables Credit card loans (1) $ 55,620 $ 57,896 Other loans Personal loans 5,534 5,490 Private student loans 5,949 5,647 Other 252 236 Total other loans 11,735 11,373 Purchased credit-impaired loans (2) 2,965 3,116 Total loan receivables 70,320 72,385 Allowance for loan losses (1,921 ) (1,869 ) Net loan receivables $ 68,399 $ 70,516 (1) Amounts include $20.9 billion and $21.6 billion underlying investors’ interest in trust debt at March 31, 2016 and December 31, 2015 and $6.2 billion and $7.2 billion in seller's interest at March 31, 2016 and December 31, 2015 , respectively. See Note 5: Credit Card and Student Loan Securitization Activities for further information. (2) Amounts include $1.6 billion and $1.7 billion of loans pledged as collateral against the notes issued from the Student Loan Corporation ("SLC") securitization trusts at March 31, 2016 and December 31, 2015 , respectively. See Note 5: Credit Card and Student Loan Securitization Activities. Credit Quality Indicators The Company regularly reviews its collection experience (including delinquencies and net charge-offs) in determining its allowance for loan losses. Information related to the delinquent and non-accruing loans in the Company’s loan portfolio is shown below by each class of loan receivables except for PCI student loans, which is shown under the heading “— Purchased Credit-Impaired Loans” (dollars in millions): 30-89 Days Delinquent 90 or More Days Delinquent Total Past Due 90 or More Days Delinquent and Accruing Total Non-accruing (1) At March 31, 2016 Credit card loans (2) $ 454 $ 480 $ 934 $ 427 $ 190 Other loans Personal loans (3) 40 14 54 13 6 Private student loans (excluding PCI) (4) 78 36 114 36 — Other 2 1 3 — 20 Total other loans (excluding PCI) 120 51 171 49 26 Total loan receivables (excluding PCI) $ 574 $ 531 $ 1,105 $ 476 $ 216 At December 31, 2015 Credit card loans (2) $ 505 $ 490 $ 995 $ 422 $ 198 Other loans Personal loans (3) 34 15 49 13 6 Private student loans (excluding PCI) (4) 84 24 108 25 — Other — 1 1 — 20 Total other loans (excluding PCI) 118 40 158 38 26 Total loan receivables (excluding PCI) $ 623 $ 530 $ 1,153 $ 460 $ 224 (1) The Company estimates that the gross interest income that would have been recorded in accordance with the original terms of non-accruing credit card loans was $8 million and $7 million for the three months ended March 31, 2016 and 2015 , respectively. The Company does not separately track the amount of gross interest income that would have been recorded in accordance with the original terms of loans. This amount was estimated based on customers' current balances and most recent interest rates. (2) Credit card loans that are 90 or more days delinquent and accruing interest include $44 million and $42 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 , respectively. (3) Personal loans that are 90 or more days delinquent and accruing interest include $4 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 . (4) Private student loans that are 90 or more days delinquent and accruing interest include $3 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 . Information related to the net charge-offs in the Company's loan portfolio is shown below by each class of loan receivables except for PCI student loans, which is shown under the heading "— Purchased Credit-Impaired Loans" (dollars in millions): For the Three Months Ended March 31, 2016 2015 Net Net Charge-off Net Net Charge-off Credit card loans $ 326 2.34 % $ 319 2.40 % Other loans Personal loans 34 2.45 % 28 2.22 % Private student loans (excluding PCI) 12 0.85 % 13 1.03 % Total other loans (excluding PCI) 46 1.59 % 41 1.58 % Net charge-offs as a percentage of total loans (excluding PCI) $ 372 2.21 % $ 360 2.26 % Net charge-offs as a percentage of total loans (including PCI) $ 372 2.11 % $ 360 2.14 % As part of credit risk management activities, on an ongoing basis, the Company reviews information related to the performance of a customer’s account with the Company as well as information from credit bureaus, such as FICO or other credit scores, relating to the customer’s broader credit performance. FICO scores are generally obtained at origination of the account and are refreshed monthly or quarterly thereafter to assist in predicting customer behavior. Historically, the Company has noted that a significant proportion of delinquent accounts have FICO scores below 660. The following table provides the most recent FICO scores available for the Company’s customers as a percentage of each class of loan receivables: Credit Risk Profile 660 and Above Less than 660 or No Score At March 31, 2016 Credit card loans 82 % 18 % Personal loans 96 % 4 % Private student loans (excluding PCI) (1) 96 % 4 % At December 31, 2015 Credit card loans 83 % 17 % Personal loans 96 % 4 % Private student loans (excluding PCI) (1) 96 % 4 % (1) PCI loans are discussed under the heading "— Purchased Credit-Impaired Loans." For private student loans, additional credit risk management activities include monitoring the amount of loans in forbearance. Forbearance allows borrowers experiencing temporary financial difficulties and willing to make payments, the ability to temporarily suspend payments. Eligible borrowers have a lifetime cap on forbearance of 12 months . At March 31, 2016 and December 31, 2015 , there were $31 million of private student loans, including PCI, in forbearance, which represent 0.5% of total student loans in repayment and forbearance. Allowance for Loan Losses The following tables provide changes in the Company’s allowance for loan losses (dollars in millions): For the Three Months Ended March 31, 2016 Credit Card Personal Loans Student Loans (1) Other Total Balance at beginning of period $ 1,554 $ 155 $ 143 $ 17 $ 1,869 Additions Provision for loan losses 362 44 17 1 424 Deductions Charge-offs (439 ) (39 ) (15 ) — (493 ) Recoveries 113 5 3 — 121 Net charge-offs (326 ) (34 ) (12 ) — (372 ) Balance at end of period $ 1,590 $ 165 $ 148 $ 18 $ 1,921 For the Three Months Ended March 31, 2015 Credit Card Personal Loans Student Loans (1) Other Total Balance at beginning of period $ 1,474 $ 120 $ 135 $ 17 $ 1,746 Additions Provision for loan losses 337 31 20 2 390 Deductions Charge-offs (428 ) (31 ) (15 ) — (474 ) Recoveries 109 3 2 — 114 Net charge-offs (319 ) (28 ) (13 ) — (360 ) Balance at end of period $ 1,492 $ 123 $ 142 $ 19 $ 1,776 (1) Includes both PCI and non-PCI private student loans. Net charge-offs of principal are recorded against the allowance for loan losses, as shown in the preceding table. Information regarding net charge-offs of interest and fee revenues on credit card and other loans is as follows (dollars in millions): For the Three Months Ended March 31, 2016 2015 Interest and fees accrued subsequently charged off, net of recoveries (recorded as a reduction of interest income) $ 69 $ 75 Fees accrued subsequently charged off, net of recoveries (recorded as a reduction to other income) $ 17 $ 20 The following tables provide additional detail of the Company’s allowance for loan losses and recorded investment in its loan portfolio by impairment methodology (dollars in millions): Credit Card Personal Loans Student Loans (3) Other Loans (4) Total At March 31, 2016 Allowance for loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 1,430 $ 149 $ 96 $ 1 $ 1,676 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 160 16 16 17 209 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 36 — 36 Total allowance for loan losses $ 1,590 $ 165 $ 148 $ 18 $ 1,921 Recorded investment in loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 54,600 $ 5,464 $ 5,896 $ 194 $ 66,154 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 1,020 70 53 58 1,201 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 2,965 — 2,965 Total recorded investment $ 55,620 $ 5,534 $ 8,914 $ 252 $ 70,320 At December 31, 2015 Allowance for loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 1,394 $ 140 $ 92 $ 1 $ 1,627 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 160 15 15 16 206 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 36 — 36 Total allowance for loan losses $ 1,554 $ 155 $ 143 $ 17 $ 1,869 Recorded investment in loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 56,877 $ 5,422 $ 5,599 $ 179 $ 68,077 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 1,019 68 48 57 1,192 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 3,116 — 3,116 Total recorded investment $ 57,896 $ 5,490 $ 8,763 $ 236 $ 72,385 (1) Loan receivables evaluated for impairment in accordance with Accounting Standards Codification ("ASC") 310-10-35 include credit card loans, personal loans and student loans collectively evaluated for impairment in accordance with ASC Subtopic 310-40, Receivables, which consists of modified loans accounted for as troubled debt restructurings. Other loans are individually evaluated for impairment and generally do not represent troubled debt restructurings. (2) The unpaid principal balance of credit card loans was $873 million and $869 million at March 31, 2016 and December 31, 2015 , respectively. The unpaid principal balance of personal loans was $69 million and $67 million at March 31, 2016 and December 31, 2015 , respectively. The unpaid principal balance of student loans was $52 million and $47 million at March 31, 2016 and December 31, 2015 , respectively. All loans accounted for as troubled debt restructurings have a related allowance for loan losses. (3) Includes both PCI and non-PCI private student loans. (4) Certain other loans, including non-performing Diners Club licensee loans, are individually evaluated for impairment. Troubled Debt Restructurings The Company has internal loan modification programs that provide relief to credit card, personal loan and student loan borrowers who are experiencing financial hardship. The internal loan modification programs include both temporary and permanent programs which vary by product. External loan modification programs are also available for credit card and personal loans. Temporary and permanent modifications on credit card and personal loans, as well as temporary modifications on student loans and certain grants of student loan forbearance, are considered to be individually impaired. In addition, loans that defaulted or graduated from modification programs or forbearance are considered to be individually impaired. As a result, the above mentioned loans are accounted for as troubled debt restructurings . For credit card customers, the temporary hardship program primarily consists of a reduced minimum payment and an interest rate reduction, both lasting for a period no longer than 12 months . The permanent workout program involves changing the structure of the loan to a fixed payment loan with a maturity no longer than 60 months and reducing the interest rate on the loan. The permanent modification program does not normally provide for the forgiveness of unpaid principal, but may allow for the reversal of certain unpaid interest or fee assessments. The Company also makes loan modifications for customers who request financial assistance through external sources, such as a consumer credit counseling agency program (referred to here as external programs). These loans typically receive a reduced interest rate but continue to be subject to the original minimum payment terms and do not normally include waiver of unpaid principal, interest or fees. To assist student loan borrowers who are experiencing temporary financial difficulties but are willing to resume making payments, the Company may offer hardship forbearance periods of up to 12 months over the life of the loan. Forbearance provides borrowers a deferment in making payments, during which time loan interest continues to accrue at contractual rates. The Company does not anticipate significant shortfalls in the contractual amount due for borrowers using a first hardship forbearance period as the historical performance of these borrowers is not significantly different from the overall portfolio. However, when a borrower is 30 or more days delinquent and granted a second hardship forbearance period, the forbearance is considered a troubled debt restructuring. In addition, the Company offers temporary reduced payment programs, which normally consist of a reduction of the minimum payment for a period of no longer than 12 months each time the program is utilized by a borrower. When a student loan borrower is enrolled in a temporary reduced payment program for 12 months or fewer over the life of the loan, the modification is not considered a troubled debt restructuring. However, when enrollment is greater than 12 months over the life of the loan, the modification is considered a troubled debt restructuring. For personal loan customers, in certain situations the Company offers various payment programs, including temporary and permanent programs. The temporary programs normally consist of a reduction of the minimum payment for a period of no longer than 12 months with the option of a final balloon payment required at the end of the loan term or an extension of the maturity date with the total term not exceeding nine years . Further, in certain circumstances the interest rate on the loan is reduced. The permanent program involves changing the terms of the loan in order to pay off the outstanding balance over a longer term and also in certain circumstances reducing the interest rate on the loan. Similar to the temporary programs, the total term may not exceed nine years . The Company also allows loan modifications for customers who request financial assistance through external sources, similar to the credit card customers discussed above. Payments are modified based on the new terms agreed upon with the credit counseling agency. Personal loans included in temporary and permanent programs are accounted for as troubled debt restructurings. The Company monitors borrower performance after using payment programs or forbearance and the Company believes the programs help to prevent defaults and are useful in assisting customers experiencing financial difficulties. The Company plans to continue to use payment programs and forbearance and, as a result, expects to have additional loans classified as troubled debt restructurings in the future. Additional information about modified loans classified as troubled debt restructurings is shown below (dollars in millions): Average recorded investment in loans Interest income recognized during period loans were impaired (1) Gross interest income that would have been recorded with original terms (2) For the Three Months Ended March 31, 2016 Credit card loans Modified credit card loans (3) $ 274 $ 12 $ 1 Internal programs $ 464 $ 3 $ 16 External programs $ 283 $ 5 $ 3 Personal loans $ 69 $ 2 $ 1 Private student loans $ 50 $ 1 N/A For the Three Months Ended March 31, 2015 Credit card loans Modified credit card loans (3) $ 255 $ 11 $ 1 Internal programs $ 452 $ 3 $ 15 External programs $ 323 $ 6 $ 3 Personal loans $ 57 $ 2 $ 1 Private student loans $ 40 $ 1 N/A (1) The Company does not separately track interest income on loans in modification programs. Amounts shown are estimated by applying an average interest rate to the average loans in the various modification programs. (2) The Company does not separately track the amount of gross interest income that would have been recorded if the loans in modification programs had not been restructured and interest had instead been recorded in accordance with the original terms. Amounts shown are estimated by applying the difference between the average interest rate earned on non-impaired loans and the average interest rate earned on loans in the modification programs to the average loans in the modification programs. (3) This balance is considered impaired, but is excluded from the internal and external program amounts reflected in this table. Represents credit card loans that were modified in troubled debt restructurings, but are no longer enrolled in troubled debt restructuring program due to noncompliance with the terms of the modification or successful completion of a program. In order to evaluate the primary financial effects that resulted from credit card loans entering into a loan modification program during the three months ended March 31, 2016 and 2015 , the Company quantified the amount by which interest and fees were reduced during the periods. During the three months ended March 31, 2016 and 2015 , the Company forgave approximately $9 million and $11 million of interest and fees as a result of accounts entering into a credit card loan modification program, respectively. The following table provides information on loans that entered a loan modification program during the period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Number of Accounts Balances Number of Accounts Balances Accounts that entered a loan modification program during the period Credit card loans Internal programs 14,967 $ 96 13,243 $ 86 External programs 7,317 $ 39 7,617 $ 39 Personal loans 1,061 $ 12 986 $ 12 Private student loans 452 $ 8 469 $ 7 The following table presents the carrying value of loans that experienced a payment default during the period that had been modified in a troubled debt restructuring during the 15 months preceding the end of each period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Number of Accounts Aggregated Outstanding Balances Upon Default Number of Accounts Aggregated Outstanding Balances Upon Default Troubled debt restructurings that subsequently defaulted Credit card loans Internal programs (1)(2) 3,001 $ 18 3,176 $ 20 External programs (1)(2) 1,699 $ 7 1,643 $ 7 Personal loans (2) 158 $ 2 151 $ 2 Private student loans (3) 197 $ 3 305 $ 4 (1) The outstanding balance upon default is the loan balance at the end of the month prior to default. Terms revert back to the pre-modification terms for customers who default from a temporary program and charging privileges remain revoked in most cases. (2) A customer defaults from a modification program after two consecutive missed payments. (3) Student loan defaults have been defined as loans that are 60 or more days delinquent. Of the account balances that defaulted as shown above for the three months ended March 31, 2016 and 2015 , approximately 37% and 43% , respectively, of the total balances were charged off at the end of the month in which they defaulted. For accounts that have defaulted from a loan modification program and have not been subsequently charged off, the balances are included in the allowance for loan loss analysis discussed above under "— Allowance for Loan Losses." Purchased Credit-Impaired Loans Purchased loans with evidence of credit deterioration since origination for which it is probable that not all contractually required payments will be collected are considered impaired at acquisition and are reported as PCI loans. The private student loans acquired in the SLC transaction, as well as the additional acquired private student loan portfolio comprise the Company’s only PCI loans at March 31, 2016 and December 31, 2015 . Total PCI student loans had an outstanding balance of $3.2 billion and $3.3 billion , including accrued interest, and a related carrying amount of $3.0 billion and $3.1 billion as of March 31, 2016 and December 31, 2015 , respectively. The following table provides changes in accretable yield for the acquired loans during each period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Balance at beginning of period $ 965 $ 1,341 Accretion into interest income (49 ) (59 ) Other changes in expected cash flows — (101 ) Balance at end of period $ 916 $ 1,181 Periodically, the Company updates the estimate of cash flows expected to be collected based on management's latest expectations of future credit losses, borrower prepayments and certain other assumptions that affect cash flows. No provision expense was recorded during the three months ended March 31, 2016 and 2015 . The allowance for PCI loan losses at March 31, 2016 and December 31, 2015 was $36 million . For the three months ended March 31, 2016 , there were no changes in other cash flow assumptions. For the three months ended March 31, 2015 changes in other cash flow assumptions resulted in a decrease in accretable yield primarily related to changes in borrower prepayment assumptions. Changes to accretable yield are recognized prospectively as an adjustment to yield over the remaining life of the pools. At March 31, 2016 , the 30 or more days delinquency and 90 or more days delinquency rates on PCI student loans (which include loans not yet in repayment) were 2.18% and 0.73% , respectively. At December 31, 2015 , the 30 or more days delinquency and 90 or more days delinquency rates on PCI student loans (which include loans not yet in repayment) were 2.53% and 0.88% , respectively. These rates include private student loans that are greater than 120 days delinquent that are covered by an indemnification agreement or insurance arrangements through which the Company expects to recover a substantial portion of the loan. The net charge-off rate on PCI student loans was 0.43% and 0.50% for the three months ended March 31, 2016 and 2015 , respectively.

Credit Card and Student Loan Se

Credit Card and Student Loan Securitization Activities	3 Months Ended
	Mar. 31, 2016
Variable Interest Entities Disclosure [Abstract]
Credit Card and Student Loan Securitization Activities	Credit Card and Student Loan Securitization Activities Credit Card Securitization Activities The Company accesses the term asset securitization market through the Discover Card Master Trust I (“DCMT”) and the Discover Card Execution Note Trust (“DCENT”), which are trusts into which credit card loan receivables are transferred (or, in the case of DCENT, into which beneficial interests in DCMT are transferred) and from which DCENT issues notes to investors. The DCENT debt structure consists of four classes of securities (DiscoverSeries Class A, B, C and D notes), with the most senior class generally receiving a triple-A rating. In order to issue senior, higher rated classes of notes, it is necessary to obtain the appropriate amount of credit enhancement, generally through the issuance of junior, lower rated or more highly subordinated classes of notes. The subordinated classes are held by wholly-owned subsidiaries of Discover Bank. The Company is exposed to credit-related risk of loss associated with trust assets as of the balance sheet date through the retention of these subordinated interests. The estimated probable incurred loss is included in the allowance for loan loss estimate. The Company’s credit card securitizations are accounted for as secured borrowings and the trusts and Discover Funding LLC are treated as consolidated subsidiaries of the Company. The Company’s retained interests in the assets of the trusts, consisting of investments in DCENT notes held by subsidiaries of Discover Bank, constitute intercompany positions which are eliminated in the preparation of the Company’s condensed consolidated statements of financial condition. Upon transfer of credit card loan receivables to the trust, the receivables and certain cash flows derived from them become restricted for use in meeting obligations to the trusts’ creditors. Further, the transferred credit card loan receivables are owned by the trust and are not available to third-party creditors of the Company. The trusts have ownership of cash balances that also have restrictions, the amounts of which are reported in restricted cash. Investment of trust cash balances is limited to investments that are permitted under the governing documents of the trusts and which have maturities no later than the related date on which funds must be made available for distribution to trust investors. With the exception of the seller’s interest in trust receivables, the Company’s interests in trust assets are generally subordinate to the interests of third-party investors and, as such, may not be realized by the Company if needed to absorb deficiencies in cash flows that are allocated to the investors in the trusts’ debt. The carrying values of these restricted assets, which are presented on the Company’s condensed consolidated statements of financial condition as relating to securitization activities, are shown in the table below (dollars in millions): March 31, December 31, Restricted cash $ 921 $ 19 Investors’ interests held by third-party investors 15,725 15,625 Investors’ interests held by wholly-owned subsidiaries of Discover Bank 5,199 6,017 Seller’s interest 6,241 7,231 Loan receivables (1) 27,165 28,873 Allowance for loan losses allocated to securitized loan receivables (1) (783 ) (783 ) Net loan receivables 26,382 28,090 Other (2) 6 5 Carrying value of assets of consolidated variable interest entities $ 27,309 $ 28,114 (1) The Company maintains its allowance for loan losses at an amount sufficient to absorb probable losses inherent in all loan receivables, which includes all loan receivables in the trusts. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company’s balance sheet in accordance with GAAP. (2) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information. The debt securities issued by the consolidated trusts are subject to credit, payment and interest rate risks on the transferred credit card loan receivables. To protect investors, the securitization structures include certain features that could result in earlier-than-expected repayment of the securities. The primary investor protection feature relates to the availability and adequacy of cash flows in the securitized pool of receivables to meet contractual requirements. Insufficient cash flows would trigger the early repayment of the securities. This is referred to as the “economic early amortization” feature. Investors are allocated cash flows derived from activities related to the accounts comprising the securitized pool of receivables, the amounts of which reflect finance charges billed, certain fee assessments, allocations of merchant discount and interchange, and recoveries on charged-off accounts. From these cash flows, investors are reimbursed for charge-offs occurring within the securitized pool of receivables and receive a contractual rate of return and Discover Bank is paid a servicing fee as servicer. Any cash flows remaining in excess of these requirements are reported to investors as excess spread. An excess spread rate of less than 0% for a contractually specified period, generally a three-month average, would trigger an economic early amortization event. In such an event, the Company would be required to seek immediate sources of replacement funding. Apart from the restricted assets related to securitization activities, the investors and the securitization trusts have no recourse to the Company’s other assets or the Company's general credit for a shortage in cash flows. Through its wholly-owned indirect subsidiary, Discover Funding LLC, the Company is required to maintain a contractual minimum level of receivables in the trust in excess of the face value of outstanding investors’ interests. This excess is referred to as the minimum seller’s interest. The required minimum seller’s interest in the pool of trust receivables, which is included in credit card loan receivables restricted for securitization investors, is set at approximately 7% in excess of the total investors’ interests (which includes interests held by third parties as well as those certificated interests held by the Company). If the level of receivables in the trust was to fall below the required minimum, the Company would be required to add receivables from the unrestricted pool of receivables, which would increase the amount of credit card loan receivables restricted for securitization investors. A decline in the amount of the excess seller’s interest could occur if balance repayments and charge-offs exceeded new lending on the securitized accounts or as a result of changes in total outstanding investors’ interests. Seller's interest is impacted by seasonality as higher balance repayments tend to occur in the first calendar year quarter. If the Company could not add enough receivables to satisfy the requirement, an early amortization (or repayment) of investors’ interests would be triggered. The Company retains significant exposure to the performance of trust assets through holdings of the seller's interest and subordinated security classes of DCENT. In addition, the Company has the right to remove a random selection of accounts, which would serve to decrease the amount of credit card loan receivables restricted for securitization investors, subject to certain requirements including that the minimum seller's interest is still met. In addition to performance measures associated with the transferred credit card loan receivables or the inability to add receivables to satisfy the seller's interest requirement, there are other events or conditions which could trigger an early amortization event, such as non-payment of principal at expected maturity. As of March 31, 2016 , no economic or other early amortization events have occurred. The table below provides information concerning investors’ interests and related excess spread (dollars in millions): At March 31, 2016 Investors’ Interests (1) Number of Series Outstanding 3-Month Rolling Average Excess Spread Discover Card Execution Note Trust (DiscoverSeries notes) $ 20,924 36 13.55 % (1) Investors’ interests include third-party interests and subordinated interests held by wholly-owned subsidiaries of Discover Bank. The Company continues to own and service the accounts that generate the loan receivables held by the trusts. Discover Bank receives servicing fees from the trusts based on a percentage of the monthly investor principal balance outstanding. Although the fee income to Discover Bank offsets the fee expense to the trusts and thus is eliminated in consolidation, failure to service the transferred loan receivables in accordance with contractual requirements could lead to a termination of the servicing rights and the loss of future servicing income, net of related expenses. Student Loan Securitization Activities The Company’s student loan securitizations are accounted for as secured borrowings and the trusts are treated as consolidated subsidiaries of the Company. Trust receivables underlying third-party investors’ interests are recorded in PCI loans and the related debt issued by the trusts is reported in long-term borrowings. The assets of the Company’s consolidated VIEs are restricted from being sold or pledged as collateral for other borrowings and the cash flows from these restricted assets may be used only to pay obligations of the trusts. Currently there are three trusts from which securities were issued to investors. Principal payments on the long-term secured borrowings are made as cash is collected on the underlying loans that are used as collateral on the secured borrowings. The Company does not have access to cash collected by the securitization trusts until cash is released in accordance with the trust indenture agreements and, for certain securitizations, no cash will be released to the Company until all outstanding trust borrowings have been repaid. Similar to the credit card securitizations, the Company continues to own and service the accounts that generate the student loan receivables held by the trusts and receives servicing fees from the trusts based on either a percentage of the principal balance outstanding or a flat fee per borrower. Although the servicing fee income offsets the fee expense related to the trusts and thus is eliminated in consolidation, failure to service the transferred loan receivables in accordance with contractual requirements could lead to a termination of the servicing rights and the loss of future servicing income, net of related expenses. Under terms of all the trust arrangements, the Company has the option, but not the obligation, to provide financial support to the trusts, but has never provided such support. A substantial portion of the credit risk associated with the securitized loans has been transferred to third parties under private credit insurance or indemnification arrangements. The carrying values of these restricted assets, which are presented on the Company’s condensed consolidated statements of financial condition as relating to securitization activities, are shown in the table below (dollars in millions): March 31, December 31, Restricted cash $ 89 $ 80 Student loan receivables (1) 1,596 1,678 Allowance for loan losses allocated to securitized loan receivables (1) (28 ) (28 ) Net student loan receivables 1,568 1,650 Carrying value of assets of consolidated variable interest entities $ 1,657 $ 1,730 (1) The Company maintains its allowance for loan losses on PCI loans sufficient to absorb probable decreases in cash flows that were previously expected. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company's balance sheet in accordance with GAAP.

Deposits

Deposits	3 Months Ended
	Mar. 31, 2016
Deposits [Abstract]
Deposits	Deposits The Company offers its deposit products to customers through two channels: (i) through direct marketing, internet origination and affinity relationships (“direct-to-consumer deposits”); and (ii) indirectly through contractual arrangements with securities brokerage firms (“brokered deposits”). Direct-to-consumer deposits include certificates of deposit, money market accounts, online savings and checking accounts and IRA certificates of deposit, while brokered deposits include certificates of deposit and sweep accounts. The following table provides a summary of interest-bearing deposit accounts (dollars in millions): March 31, December 31, Certificates of deposit in amounts less than $100,000 (1) $ 19,728 $ 20,491 Certificates of deposit in amounts $100,000 or greater (2) 5,516 5,228 Savings deposits, including money market deposit accounts 22,811 21,375 Total interest-bearing deposits (1) $ 48,055 $ 47,094 (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information. (2) Includes $1.2 billion and $1.1 billion in certificates of deposit greater than $250,000, the Federal Deposit Insurance Corporation ("FDIC") insurance limit, as of March 31, 2016 and December 31, 2015 , respectively. The following table summarizes certificates of deposit in amounts of $100,000 or greater by contractual maturity (dollars in millions): Maturity Period March 31, 2016 Three months or less $ 530 Over three months through six months 742 Over six months through twelve months 1,536 Over twelve months 2,708 Total $ 5,516 The following table summarizes certificates of deposit maturing over the remainder of this year, over each of the next four years, and thereafter (dollars in millions): Year March 31, 2016 2016 $ 8,335 2017 6,792 2018 3,607 2019 1,966 2020 1,938 Thereafter 2,606 Total $ 25,244

Long-Term Borrowings

Long-Term Borrowings	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Long-Term Borrowings	Long-Term Borrowings Long-term borrowings consist of borrowings having original maturities of one year or more. The following table provides a summary of the Company’s long-term borrowings and weighted-average interest rates on outstanding balances (dollars in millions): March 31, 2016 December 31, 2015 Maturity Interest Weighted-Average Interest Rate Outstanding Amount Outstanding Amount Securitized Debt Fixed-rate asset-backed securities (1)(8) 2016 - 2020 1.04% - 5.65% 2.05% $ 9,268 $ 9,152 Floating-rate asset-backed securities (2)(3)(8) 2016 - 2019 0.62% - 0.89% 0.79% 6,441 6,440 Total Discover Card Master Trust I and Discover Card Execution Note Trust (8) 15,709 15,592 Floating-rate asset-backed securities (4)(5)(6)(7) 2031 - 2042 0.79% - 4.25% 2.21% 1,070 1,143 Total SLC Private Student Loan Trusts 1,070 1,143 Total long-term borrowings - owed to securitization investors (8) 16,779 16,735 Discover Financial Services (Parent Company) Fixed-rate senior notes (1)(8) 2017 - 2025 3.75%-10.25% 4.75% 2,073 2,066 Fixed-rate retail notes (8) 2021 - 2028 3.00% - 4.40% 3.94% 77 39 Discover Bank Fixed-rate senior bank notes (1)(8) 2018 - 2026 2.00% - 4.25% 3.16% 5,128 5,115 Fixed-rate subordinated bank notes (8) 2019 - 2020 7.00% - 8.70% 7.49% 695 695 Total long-term borrowings (8) $ 24,752 $ 24,650 (1) The Company uses interest rate swaps to hedge portions of these long-term borrowings against changes in fair value attributable to changes in London Interbank Offered Rate (“LIBOR”). Use of these interest rate swaps impacts carrying value of the debt. (2) Discover Card Execution Note Trust floating-rate asset-backed securities include issuances with the following interest rate terms: 1-month LIBOR + 18 to 45 basis points and 3-month LIBOR + 20 basis points as of March 31, 2016 . (3) The Company uses interest rate swaps to manage its exposure to changes in interest rates related to future cash flows resulting from interest payments on a portion of these long-term borrowings. There is no impact on debt carrying value from use of these interest rate swaps. See Note 15: Derivatives and Hedging Activities. (4) SLC Private Student Loan Trusts floating-rate asset-backed securities include issuances with the following interest rate terms: 3-month LIBOR + 17 to 45 basis points , Prime rate + 75 to 100 basis points and 1-month LIBOR + 350 basis points as of March 31, 2016 . (5) The Company acquired an interest rate swap related to the securitized debt assumed in the SLC transaction. The swap does not qualify for hedge accounting and has no impact on debt carrying value. See Note 15: Derivatives and Hedging Activities. (6) Repayment of this debt is dependent upon the timing of principal and interest payments on the underlying student loans. The dates shown represent final maturity dates. (7) Includes $302 million of senior notes maturing in 2031, $621 million of senior and subordinated notes maturing in 2036 and $147 million of senior notes maturing in 2042 as of March 31, 2016 . (8) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information. The following table summarizes long-term borrowings maturing over the remainder of this year, over each of the next four years, and thereafter (dollars in millions): Year March 31, 2016 2016 $ 2,150 2017 5,099 2018 5,273 2019 4,270 2020 3,094 Thereafter 4,866 Total $ 24,752 The Company has access to committed undrawn capacity through private securitizations to support the funding of its credit card loan receivables. As of March 31, 2016 , the total commitment of secured credit facilities through private providers was $6.0 billion , none of which was drawn as of March 31, 2016 . Access to the unused portions of the secured credit facilities is subject to the terms of the agreements with each of the providers which have various expirations in 2017 and 2018. Borrowings outstanding under each facility bear interest at a margin above LIBOR or the asset-backed commercial paper costs of each individual conduit provider. The terms of each agreement provide for a commitment fee to be paid on the unused capacity and include various affirmative and negative covenants, including performance metrics and legal requirements similar to those required to issue any term securitization transaction.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Changes in each component of accumulated other comprehensive income (loss) ("AOCI") were as follows (dollars in millions): Unrealized Gain on Available-for-Sale Investment Securities, Net of Tax Loss on Cash Flow Hedges, Net of Tax Pension Plan Loss, Net of Tax AOCI For the Three Months Ended March 31, 2016 Balance at December 31, 2015 $ — $ (20 ) $ (140 ) $ (160 ) Net change 14 (26 ) — (12 ) Balance at March 31, 2016 $ 14 $ (46 ) $ (140 ) $ (172 ) For the Three Months Ended March 31, 2015 Balance at December 31, 2014 $ 23 $ (7 ) $ (154 ) $ (138 ) Net change — (23 ) — (23 ) Balance at March 31, 2015 $ 23 $ (30 ) $ (154 ) $ (161 ) The table below presents each component of other comprehensive income (loss) ("OCI") before reclassifications and amounts reclassified from AOCI for each component of OCI before- and after-tax (dollars in millions): Before Tax Tax (Expense) Benefit Net of Tax For the Three Months Ended March 31, 2016 Available-for-Sale Investment Securities Net unrealized holding gain arising during the period $ 23 $ (9 ) $ 14 Amounts reclassified from AOCI — — — Net change $ 23 $ (9 ) $ 14 Cash Flow Hedges Net unrealized loss arising during the period $ (52 ) $ 21 $ (31 ) Amounts reclassified from AOCI 9 (4 ) 5 Net change $ (43 ) $ 17 $ (26 ) For the Three Months Ended March 31, 2015 Available-for-Sale Investment Securities Net unrealized holding gain arising during the period $ 8 $ (3 ) $ 5 Amounts reclassified from AOCI (8 ) 3 (5 ) Net change $ — $ — $ — Cash Flow Hedges Net unrealized loss arising during the period $ (47 ) $ 17 $ (30 ) Amounts reclassified from AOCI 12 (5 ) 7 Net change $ (35 ) $ 12 $ (23 )

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following table presents the calculation of the Company's effective income tax rate (dollars in millions, except effective income tax rate): For the Three Months Ended March 31, 2016 2015 Income before income tax expense $ 914 $ 908 Income tax expense $ 339 $ 322 Effective income tax rate 37.1 % 35.5 % Income tax expense and the effective tax rate increased $17 million and 1.6% , respectively, for the three months ended March 31, 2016 as compared to the same period in 2015 . The 2015 period included a one-time benefit related to unrecognized tax benefits from resolving certain tax matters. The Company is subject to examination by the Internal Revenue Service ("IRS") and the tax authorities in various state and foreign tax jurisdictions. The tax years under examination vary by jurisdiction. The Company regularly assesses the likelihood of additional assessments or settlements in each of the taxing jurisdictions resulting from these examinations. The Company believes that its reserves are sufficient to cover any tax, penalties and interest that could result from such examinations. On April 6, 2016, the Company was notified that the United States Congress Joint Committee on Taxation (“JCT”) approved an audit settlement for tax years 1999-2005 and 2006-2007. The 2008-2010 audit is currently under administrative appeals. This JCT approval resolves issues that were disputed through several tax audit cycles (1999-2005, 2006-2007, 2008-2010 and 2011-2012). The Company will apply the settlement methodology to all open audit cycles. As a result of these events, the Company anticipates recognizing both the unrecognized tax benefit receivables and payables of $337 million as applicable to each tax period and reversing the corresponding accrued interest which will result in a reduction of tax expense of approximately $40 million , in the second quarter of 2016 . The 1999-2005 and 2006-2007 audit periods pre-date the Company’s spin-off, therefore settlement from those years will be governed by the Company’s Tax Sharing Agreement with Morgan Stanley. Settlement of tax years subsequent to the spin-off date, June 30, 2007, will be made directly with the IRS.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table presents the calculation of basic and diluted earnings per share ("EPS") (in millions, except per share amounts): For the Three Months Ended March 31, 2016 2015 Numerator Net income $ 575 $ 586 Preferred stock dividends (9 ) (9 ) Net income available to common stockholders 566 577 Income allocated to participating securities (4 ) (4 ) Net income allocated to common stockholders $ 562 $ 573 Denominator Weighted-average shares of common stock outstanding 417 448 Basic earnings per common share $ 1.35 $ 1.28 Diluted earnings per common share $ 1.35 $ 1.28 Anti-dilutive securities were not material and had no impact on the computation of diluted EPS for the three months ended March 31, 2016 and 2015 .

Capital Adequacy

Capital Adequacy	3 Months Ended
	Mar. 31, 2016
Regulatory Capital Requirements [Abstract]
Capital Adequacy	Capital Adequacy The Company is subject to the capital adequacy guidelines of the Federal Reserve, and Discover Bank, the Company’s main banking subsidiary, is subject to various regulatory capital requirements as administered by the FDIC. Failure to meet minimum capital requirements can result in the initiation of certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the financial position and results of the Company and Discover Bank. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and Discover Bank must meet specific capital guidelines that involve quantitative measures of assets, liabilities and certain off-balance sheet items, as calculated under regulatory guidelines. Capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. In 2013, the Federal Reserve, the Office of the Comptroller of the Currency and the FDIC issued final capital rules under the Basel Committee’s December 2010 framework (referred to as “Basel III”) establishing a new comprehensive capital framework for U.S. banking organizations. The final capital rules of Basel III ("Basel III rules") substantially revise Basel I rules regarding the risk-based capital requirements applicable to bank holding companies and depository institutions, including the Company. The Basel III rules became effective for the Company on January 1, 2015. This timing is based on the Company being classified as a "Standardized Approach" entity. Among other things, the Basel III rules (i) introduced a new capital measure called Common Equity Tier 1 (“CET1”), (ii) specify that Tier 1 capital consists of CET1 and additional Tier 1 capital instruments meeting specified requirements, (iii) apply most deductions/adjustments to regulatory capital measures to CET1 and not to the other components of capital, thus potentially requiring higher levels of CET1 in order to meet minimum ratios, and (iv) expand the scope of the deductions/adjustments from capital as compared to existing regulations. The Basel III minimum capital ratios as of January 1, 2015 are as follows: • 8.0% Total capital (i.e., Tier 1 plus Tier 2) to risk-weighted assets; • 6.0% Tier 1 capital (i.e., CET1 plus Additional Tier 1) to risk-weighted assets; • 4.0% Tier 1 capital to average consolidated assets as reported on consolidated financial statements (known as the “leverage ratio”); and • 4.5% CET1 to risk-weighted assets. As of March 31, 2016 , the Company and Discover Bank met all Basel III minimum capital ratio requirements. The Company and Discover Bank also met the requirements to be considered "well-capitalized" under prompt corrective action regulations and there have been no conditions or events that management believes have changed the Company's or Discover Bank's category. To be categorized as “well-capitalized,” the Company and Discover Bank must maintain minimum capital ratios as set forth in the table below. The following table shows the actual capital amounts and ratios of the Company and Discover Bank and comparisons of each to the regulatory minimum and “well-capitalized” requirements (dollars in millions): Actual Minimum Capital Requirements Capital Requirements To Be Classified as Well-Capitalized Amount Ratio Amount Ratio Amount Ratio March 31, 2016 Total capital (to risk-weighted assets) Discover Financial Services $ 12,463 16.8 % $ 5,936 ≥8.0% $ 7,421 ≥10.0% Discover Bank $ 12,008 16.4 % $ 5,876 ≥8.0% $ 7,345 ≥10.0% Tier 1 capital (to risk-weighted assets) Discover Financial Services $ 11,153 15.0 % $ 4,452 ≥6.0% $ 5,936 ≥8.0% Discover Bank $ 10,061 13.7 % $ 4,407 ≥6.0% $ 5,876 ≥8.0% Tier 1 capital (to average assets) Discover Financial Services $ 11,153 12.8 % $ 3,493 ≥4.0% $ 4,366 ≥5.0% Discover Bank $ 10,061 11.6 % $ 3,459 ≥4.0% $ 4,323 ≥5.0% CET1 capital (to risk-weighted assets) (Basel III transition) Discover Financial Services $ 10,593 14.3 % $ 3,339 ≥4.5% $ 4,823 ≥6.5% Discover Bank $ 10,061 13.7 % $ 3,305 ≥4.5% $ 4,774 ≥6.5% December 31, 2015 (1) Total capital (to risk-weighted assets) Discover Financial Services $ 12,497 16.5 % $ 6,052 ≥8.0% $ 7,565 ≥10.0% Discover Bank $ 11,905 15.9 % $ 5,991 ≥8.0% $ 7,488 ≥10.0% Tier 1 capital (to risk-weighted assets) Discover Financial Services $ 11,126 14.7 % $ 4,539 ≥6.0% $ 6,052 ≥8.0% Discover Bank $ 9,941 13.3 % $ 4,493 ≥6.0% $ 5,991 ≥8.0% Tier 1 capital (to average assets) Discover Financial Services $ 11,126 12.9 % $ 3,446 ≥4.0% $ 4,307 ≥5.0% Discover Bank $ 9,941 11.7 % $ 3,410 ≥4.0% $ 4,263 ≥5.0% CET1 capital (to risk-weighted assets) (Basel III transition) Discover Financial Services $ 10,566 14.0 % $ 3,404 ≥4.5% $ 4,917 ≥6.5% Discover Bank $ 9,941 13.3 % $ 3,370 ≥4.5% $ 4,867 ≥6.5% (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	3 Months Ended
	Mar. 31, 2016
Commitments Contingencies and Guarantees [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees Lease Commitments The Company leases various office space and equipment under capital and non-cancelable operating leases, which expire at various dates through 2028. Future minimum payments on capital leases were not material at March 31, 2016. The following table shows future minimum payments on non-cancelable operating leases with original terms in excess of one year (dollars in millions): March 31, 2016 2016 $ 11 2017 12 2018 11 2019 9 2020 7 Thereafter 34 Total minimum lease payments $ 84 Unused Commitments to Extend Credit At March 31, 2016 , the Company had unused commitments to extend credit for loans of approximately $182.8 billion . Such commitments arise primarily from agreements with customers for unused lines of credit on certain credit cards and certain other loan products, provided there is no violation of conditions in the related agreements. These commitments, substantially all of which the Company can terminate at any time and which do not necessarily represent future cash requirements, are periodically reviewed based on account usage, customer creditworthiness and loan qualification. Securitizations Representations and Warranties As part of the Company’s financing activities, the Company provides representations and warranties that certain assets pledged as collateral in secured borrowing arrangements conform to specified guidelines. Due diligence is performed by the Company which is intended to ensure that asset guideline qualifications are met. If the assets pledged as collateral do not meet certain conforming guidelines, the Company may be required to replace, repurchase or sell such assets. In its credit card securitization activities, the Company would replace nonconforming receivables through the allocation of excess seller’s interest or from additional transfers from the unrestricted pool of receivables. If the Company could not add enough receivables to satisfy the requirement, an early amortization (or repayment) of investors’ interests would be triggered. In its student loan securitizations, the Company would generally repurchase the loans from the trust at the outstanding principal amount plus interest. The maximum potential amount of future payments the Company could be required to make would be equal to the current outstanding balances of third-party investor interests in credit card asset-backed securities plus the principal amount of any other outstanding secured borrowings. The Company has recorded substantially all of the maximum potential amount of future payments in long-term borrowings on the Company’s condensed consolidated statements of financial condition. The Company has not recorded any incremental contingent liability associated with its secured borrowing representations and warranties. Management believes that the probability of having to replace, repurchase or sell assets pledged as collateral under secured borrowing arrangements, including an early amortization event, is low. Mortgage Loans Representations and Warranties The Company sold loans it originated to investors on a servicing-released basis and the risk of loss or default by the borrower is generally transferred to the investor. However, the Company was required by these investors to make certain representations and warranties relating to credit information, loan documentation and collateral. These representations and warranties may extend through the contractual life of the mortgage loan, even though the Company closed the mortgage origination business. Subsequent to the sale, if underwriting deficiencies, borrower fraud or documentation defects are discovered in individual mortgage loans, the Company may be obligated to repurchase the respective mortgage loan or indemnify the investors for any losses from borrower defaults if such deficiency or defect cannot be cured within the specified period following discovery. The Company has established a repurchase reserve based on expected losses. At March 31, 2016 , this amount was not material and was included in accrued expenses and other liabilities on the condensed consolidated statements of financial condition. Guarantees The Company has obligations under certain guarantee arrangements, including contracts and indemnification agreements, which contingently require the Company to make payments to the guaranteed party based on changes in an underlying asset, liability or equity security of a guaranteed party, rate or index. Also included as guarantees are contracts that contingently require the Company to make payments to a guaranteed party based on another entity’s failure to perform under an agreement. The Company’s use of guarantees is disclosed below by type of guarantee. Counterparty Settlement Guarantees Diners Club and DFS Services LLC (on behalf of PULSE) have various counterparty exposures, which are listed below. • Merchant Guarantee . Diners Club has entered into contractual relationships with certain international merchants, which generally include travel-related businesses, for the benefit of all Diners Club licensees. The licensees hold the primary liability to settle the transactions of their customers with these merchants. However, Diners Club retains a counterparty exposure if a licensee fails to meet its financial payment obligation to one of these merchants. • ATM Guarantee. PULSE entered into contractual relationships with certain international ATM acquirers in which DFS Services LLC retains counterparty exposure if an issuer fails to fulfill its settlement obligation. The maximum potential amount of future payments related to such contingent obligations is dependent upon the transaction volume processed between the time a counterparty defaults on its settlement and the time at which the Company disables the settlement of any further transactions for the defaulting party, which could be one month depending on the type of guarantee/counterparty. However, there is no limitation on the maximum amount the Company may be liable to pay. The actual amount of the potential exposure cannot be quantified as the Company cannot determine whether particular counterparties will fail to meet their settlement obligations. While the Company has some contractual remedies to offset these counterparty settlement exposures (such as letters of credit or pledged deposits), in the event that all licensees and/or issuers were to become unable to settle their transactions, the Company estimates its maximum potential counterparty exposures to these settlement guarantees, based on historical transaction volume, would be as follows (dollars in millions): March 31, Diners Club: Merchant guarantee $ 142 PULSE: ATM guarantee $ 1 With regard to the counterparty settlement guarantees discussed above, the Company believes that the estimated amounts of maximum potential future payments are not representative of the Company’s actual potential loss exposure given Diners Club’s and PULSE’s insignificant historical losses from these counterparty exposures. As of March 31, 2016 , the Company had not recorded any contingent liability in the condensed consolidated financial statements for these counterparty exposures, and management believes that the probability of any payments under these arrangements is low. Merchant Chargeback Guarantees The Company operates the Discover Network, issues payment cards and permits third parties to issue payment cards. The Company is contingently liable for certain transactions processed on the Discover Network in the event of a dispute between the payment card customer and a merchant. The contingent liability arises if the disputed transaction involves a merchant or merchant acquirer with whom the Discover Network has a direct relationship. If a dispute is resolved in the customer’s favor, the Discover Network will credit or refund the disputed amount to the Discover Network card issuer, who in turn credits its customer’s account. The Discover Network will then charge back the disputed amount of the payment card transaction to the merchant or merchant acquirer, where permitted by the applicable agreement, to seek recovery of amounts already paid to the merchant for payment card transactions. If the Discover Network is unable to collect the amount subject to dispute from the merchant or merchant acquirer ( e.g. , in the event of merchant default or dissolution) or after expiration of the time period for chargebacks in the applicable agreement, the Discover Network will bear the loss for the amount credited or refunded to the customer. In most instances, a loss by the Discover Network is unlikely to arise in connection with payments on card transactions because most products or services are delivered when purchased and credits are issued by merchants on returned items in a timely fashion, thus minimizing the likelihood of cardholder disputes with respect to amounts paid by the Discover Network. However, where the product or service is not scheduled to be provided to the customer until a later date following the purchase, the likelihood of a contingent payment obligation by the Discover Network increases. Losses related to merchant chargebacks were not material for the three months ended March 31, 2016 and 2015 . The maximum potential amount of obligations of the Discover Network arising as a result of such contingent obligations is estimated to be the portion of the total Discover Network transaction volume processed to date for which timely and valid disputes may be raised under applicable law and relevant issuer and customer agreements. There is no limitation on the maximum amount the Company may be liable to pay to issuers. However, the Company believes that such amount is not representative of the Company’s actual potential loss exposure based on the Company’s historical experience. The actual amount of the potential exposure cannot be quantified as the Company cannot determine whether the current or cumulative transaction volumes may include or result in disputed transactions. The table below summarizes certain information regarding merchant chargeback guarantees (in millions): For the Three Months Ended March 31, 2016 2015 Aggregate sales transaction volume (1) $ 31,281 $ 29,498 (1) Represents period transactions processed on the Discover Network for which a potential liability exists that, in aggregate, can differ from credit card sales volume. The Company did not record any contingent liability in the condensed consolidated financial statements for merchant chargeback guarantees as of March 31, 2016 or December 31, 2015 . The Company mitigates the risk of potential loss exposure by withholding settlement from merchants, obtaining third-party guarantees, or obtaining escrow deposits or letters of credit from certain merchant acquirers or merchants that are considered higher risk due to various factors such as time delays in the delivery of products or services. The table below provides information regarding escrow deposits and settlement withholdings, which are recorded in interest-bearing deposit accounts and accrued expenses and other liabilities on the Company’s condensed consolidated statements of financial condition, respectively (dollars in millions): March 31, December 31, Settlement withholdings and escrow deposits $ 6 $ 7

Litigation and Regulatory Matte

Litigation and Regulatory Matters	3 Months Ended
	Mar. 31, 2016
Loss Contingency [Abstract]
Litigation and Regulatory Matters	Litigation and Regulatory Matters In the normal course of business, from time to time, the Company has been named as a defendant in various legal actions, including arbitrations, class actions and other litigation, arising in connection with its activities. Certain of the actual or threatened legal actions include claims for substantial compensatory and/or punitive damages or claims for indeterminate amounts of damages. The litigation process is not predictable and can lead to unexpected results. The Company contests liability and/or the amount of damages as appropriate in each pending matter. The Company has historically relied on the arbitration clause in its cardmember agreements, which has in some instances limited the costs of, and the Company’s exposure to litigation, but there can be no assurance that the Company will continue to be successful in enforcing its arbitration clause in the future. Legal challenges to the enforceability of these clauses have led most card issuers, and may cause the Company, to discontinue their use. The Company is involved in pending legal actions challenging its arbitration clause. Bills are periodically introduced in Congress to directly or indirectly prohibit the use of pre-dispute arbitration clauses, and the Dodd-Frank Wall Street Reform and Consumer Protection Act (the "Dodd-Frank Act") authorized the Consumer Financial Protection Bureau (the "CFPB") to conduct a study on pre-dispute arbitration clauses and, based on the study, potentially limit or ban arbitration clauses. On March 10, 2015, the CFPB released its report to Congress on pre-dispute arbitration as required by the Dodd-Frank Act. On October 7, 2015, the CFPB published a potential rulemaking on arbitration agreements that would (i) effectively ban consumer financial companies from using arbitration clauses to prevent class action cases and (ii) require records of all other arbitrations to be provided to the CFPB for potential publication on its website. The timing and provisions of any final rule are uncertain at this time. The Company is also involved, from time to time, in other reviews, investigations and proceedings (both formal and informal) by governmental agencies regarding the Company’s business including, among other matters, consumer regulatory, accounting, tax and other operational matters, some of which may result in significant adverse judgments, settlements, fines, penalties, injunctions, decreases in regulatory ratings, customer restitution or other relief, which could materially impact the Company's condensed consolidated financial statements, increase its cost of operations, or limit its ability to execute its business strategies and engage in certain business activities. For example, Discover Bank and Discover Financial Services have been the subject of actions by the FDIC and the Federal Reserve, respectively, with respect to anti-money laundering and related compliance programs as described more fully below. In addition, certain subsidiaries of the Company are subject to a consent order with the CFPB regarding certain student loan servicing practices, as described below. Regulatory actions generally can include demands for civil money penalties, changes to certain business practices and customer restitution. Supervisory actions related to anti-money laundering and related laws and regulations will limit for a period of time the Company's ability to enter into certain types of acquisitions and make certain types of investments. In accordance with applicable accounting guidance, the Company establishes an accrued liability for legal and regulatory matters when those matters present loss contingencies which are both probable and estimable. Litigation and regulatory settlement related expense was insignificant for the three months ended March 31, 2016 and was $23 million for the three months ended March 31, 2015 . There may be an exposure to loss in excess of any amounts accrued. The Company believes the estimate of the aggregate range of reasonably possible losses (meaning those losses the likelihood of which is more than remote but less than likely) in excess of the amounts that the Company has accrued for legal and regulatory proceedings is up to $160 million . This estimated range of reasonably possible losses is based upon currently available information for those proceedings in which the Company is involved, takes into account the Company’s best estimate of such losses for those matters for which an estimate can be made, and does not represent the Company’s maximum potential loss exposure. Various aspects of the legal proceedings underlying the estimated range will change from time to time and actual results may vary significantly from the estimate. The Company’s estimated range above involves significant judgment, given the varying stages of the proceedings, the existence of numerous yet to be resolved issues, the breadth of the claims (often spanning multiple years and, in some cases, a wide range of business activities), unspecified damages and/or the novelty of the legal issues presented. The outcome of pending matters could be material to the Company’s condensed consolidated financial condition, operating results and cash flows for a particular future period, depending on, among other things, the level of the Company’s income for such period, and could adversely affect the Company’s reputation. On July 5, 2012, the Antitrust Division of the United States Department of Justice (the “Division”) issued a CID to the Company seeking information regarding an investigation related to potential violations of Sections 1 and 2 of the Sherman Act, 15 U.S.C. §§1-2, by an unidentified party other than Discover. The CID seeks documents, data and narrative responses to several interrogatories and document requests, related to the debit card market. A CID is a request for information in the course of a civil investigation and does not constitute the commencement of legal proceedings. The Division is permitted by statute to issue a CID to anyone whom it believes may have information relevant to an investigation. The receipt of a CID does not presuppose that there is probable cause to believe that a violation of the antitrust laws has occurred or that a formal complaint ultimately will be filed. The Company is cooperating with the Division in connection with the CID. On August 14, 2012, a purported shareholder, James Groen, filed a shareholder derivative action in the U.S. District Court for the Northern District of Illinois (Groen v. Nelms et al.) against the Company’s board of directors, certain current and former officers and directors and the Company as nominal defendant. On August 27, 2012, a second purported shareholder, the Charter Township of Clinton Police and Fire Retirement System, filed a substantially identical shareholder derivative action in the same court against the same parties (Charter Township of Clinton Police and Fire Retirement System v. Nelms et al.). On September 25, 2012, the actions were consolidated, and on February 19, 2013, the plaintiffs filed an amended consolidated complaint. The consolidated complaint asserts claims against the board of directors and certain current and former officers and directors for alleged breach of fiduciary duty, corporate waste and unjust enrichment arising out of the Company’s alleged violations of the law in connection with the marketing and sale of its protection products. The relief sought in the consolidated complaint includes changes to the Company’s corporate governance procedures; unspecified damages, injunctive relief, restitution and disgorgement from the individual defendants; and attorneys’ fees. On April 5, 2013, the defendants filed a motion to dismiss the amended consolidated complaint, and on June 5, 2013, briefing on the motion to dismiss was completed. On March 23, 2015, the Court granted the defendants’ motion to dismiss the amended consolidated shareholder derivative complaint without prejudice, while also allowing the plaintiffs until April 10, 2015 to request permission to file a further amended complaint in order to avoid having the case dismissed with prejudice. On April 6, 2015, the plaintiffs filed a motion requesting reconsideration by the Court of its order dismissing the complaint. In addition, on April 10, 2015, the plaintiffs filed a motion requesting permission to file a further amended complaint. On March 17, 2016, the Court denied both the motion for reconsideration and motion for leave to amend and dismissed the case with prejudice. On April 18, 2016, the plaintiffs filed a notice of appeal. On September 2, 2014, a purported shareholder, Steamfitters Local 449 Pension Fund, filed a shareholder derivative action in the Circuit Court of the Nineteenth Judicial Circuit, Lake County, Illinois (Steamfitters Local 449 Pension Fund, derivatively on behalf of Discover Financial Services v. David W. Nelms, et al.) against the Company’s board of directors and certain current and former officers and directors of the Company. The complaint asserts claims for alleged breach of fiduciary duty, corporate waste and unjust enrichment arising out of the Company’s alleged violations of the law in connection with the marketing and sale of protection products. The relief sought in the consolidated complaint includes changes to the Company’s corporate governance procedures, unspecified damages, restitution and disgorgement from the individual defendants and attorneys’ fees. On September 25, 2014, the court entered an order staying the case until 30 days after the U.S. District Court for the Northern District of Illinois enters an order on defendants’ motion to dismiss the amended consolidated complaint in Groen v. Nelms et al. and Charter Township of Clinton Police and Fire Retirement System v. Nelms et al. (as consolidated, the Groen and Charter Township cases are now captioned: In re Discover Financial Services Derivative Litigation). The case remains stayed. On May 26, 2015, the Company entered into a written agreement with the Federal Reserve Bank of Chicago where the Company agreed to enhance the Company’s enterprise-wide anti-money laundering and related compliance programs. The agreement does not include civil money penalties. This agreement follows the consent order that Discover Bank entered into with the FDIC on June 13, 2014 related to Discover Bank’s anti-money laundering and related compliance programs. In the consent order, Discover Bank agreed to, among other things, enhance its anti-money laundering and related compliance programs. On July 9, 2015, a class action lawsuit was filed against the Company in the U.S. District Court for the Northern District of Illinois (Polly Hansen v. Discover Financial Services and Discover Home Loans, Inc.). The plaintiff alleges that the Company contacted her, and members of the class she seeks to represent, on their cellular and residential telephones without their express consent or after consent was revoked in violation of the Telephone Consumer Protection Act ("TCPA"). Plaintiff seeks statutory damages for alleged negligent and willful violations of the TCPA, attorneys' fees, costs and injunctive relief. The TCPA provides for statutory damages of $500 for each violation ( $1,500 for willful violations). The Company will seek to vigorously defend against all claims asserted by the plaintiff. On March 8, 2016, Summer Davenport was substituted as lead plaintiff for Polly Hansen. On July 22, 2015, the Company announced that its subsidiaries, Discover Bank, The Student Loan Corporation and Discover Products, Inc. (the “Discover Subsidiaries”), agreed to a consent order with the CFPB resolving the agency’s investigation with respect to certain student loan servicing practices. The CFPB’s investigation into these practices has been previously disclosed by the Company, initially in February 2014. The order requires the Discover Subsidiaries to provide redress of approximately $16 million to consumers who may have been affected by the activities described in the order related to certain collection calls, overstatements of minimum payment due amounts in billing statements, and provision of interest paid information to consumers, and provide regulatory disclosures with respect to loans acquired in default. In addition, the Discover Subsidiaries are required to pay a $2.5 million civil money penalty to the CFPB. As required by the consent order, on October 19, 2015, the Discover Subsidiaries submitted to the CFPB a redress plan and a compliance plan designed to ensure that the Discover Subsidiaries provide redress and otherwise comply with the terms of the order. On September 4, 2015, the District Attorney of Trinity County, California filed a protection products lawsuit against the Company in California state court (The People of the State of California Ex Rel, Eric L. Heryford, District Attorney, Trinity County v. Discover Financial Services, et al.). The District Attorney subsequently dismissed this lawsuit on February 19, 2016 and filed a new complaint in federal court in the Eastern District of California on March 4, 2016 alleging the same cause of action. An amended complaint was filed on March 25, 2016. The lawsuit asserts various claims under California's Unfair Competition Law with respect to the Company's marketing and administration of various protection products. Plaintiff seeks declaratory relief, statutory civil penalties, and attorneys’ fees. The Company is not in a position at this time to assess the likely outcome or its exposure, if any, with respect to this matter, but will seek to vigorously defend against all claims asserted by the plaintiff. On March 8, 2016, a class action lawsuit was filed against the Company in the U.S. District Court for the Northern District of California (B&R Supermarket, Inc., d/b/a Milam’s Market, et al. v. Visa, Inc. et al.) alleging violations of the Sherman Antitrust Act, California's Cartwright Act, and unjust enrichment. Plaintiffs allege a conspiracy to shift fraud liability to merchants with the migration to the EMV security standard and chip technology. Plaintiffs seek damages, attorneys' fees, costs and injunctive relief. The Company is not in a position at this time to assess the likely outcome or its exposure, if any, with respect to this matter, but will seek to vigorously defend against all claims asserted by the plaintiffs.

Fair Value Measurements and Dis

Fair Value Measurements and Disclosures	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements and Disclosures	Fair Value Measurements and Disclosures Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. ASC Topic 820, Fair Value Measurement , provides a three-level hierarchy for classifying financial instruments, which is based on whether the inputs to the valuation techniques used to measure the fair value of each financial instrument are observable or unobservable. It also requires certain disclosures about those measurements. The three-level valuation hierarchy is as follows: • Level 1 : Fair values determined by Level 1 inputs are defined as those that utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access. • Level 2 : Fair values determined by Level 2 inputs are those that utilize inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active or inactive markets, quoted prices for the identical assets in an inactive market, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals. The Company evaluates factors such as the frequency of transactions, the size of the bid-ask spread and the significance of adjustments made when considering transactions involving similar assets or liabilities to assess the relevance of those observed prices. If relevant and observable prices are available, the fair values of the related assets or liabilities would be classified as Level 2. • Level 3 : Fair values determined by Level 3 inputs are those based on unobservable inputs and include situations where there is little, if any, market activity for the asset or liability being valued. In instances in which the inputs used to measure fair value may fall into different levels of the fair value hierarchy, the level in the fair value hierarchy within which the fair value measurement in its entirety is classified is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company may utilize both observable and unobservable inputs in determining the fair values of financial instruments classified within the Level 3 category. The determination of classification of its financial instruments within the fair value hierarchy is performed at least quarterly by the Company. For transfers in and out of the levels of the fair value hierarchy, the Company discloses the fair value measurement based on the value immediately preceding the transfer. The Company's assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and involves consideration of factors specific to the asset or liability. Furthermore, certain techniques used to measure fair value involve some degree of judgment and, as a result, are not necessarily indicative of the amounts the Company would realize in a current market exchange. During the three months ended March 31, 2016 , there were no changes to the Company's valuation techniques that had, or are expected to have, a material impact on the Company's condensed consolidated financial position or results of operations. Assets and Liabilities Measured at Fair Value on a Recurring Basis Assets and liabilities measured at fair value on a recurring basis are as follows (dollars in millions): Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance at March 31, 2016 Assets U.S. Treasury securities $ 1,180 $ — $ — $ 1,180 U.S. government agency securities 492 — — 492 Residential mortgage-backed securities - Agency — 1,152 — 1,152 Available-for-sale investment securities $ 1,672 $ 1,152 $ — $ 2,824 Derivative financial instruments $ — $ 58 $ — $ 58 Liabilities Derivative financial instruments $ — $ 78 $ — $ 78 Balance at December 31, 2015 Assets U.S. Treasury securities $ 1,272 $ — $ — $ 1,272 U.S. government agency securities 494 — — 494 Residential mortgage-backed securities - Agency — 1,197 — 1,197 Available-for-sale investment securities $ 1,766 $ 1,197 $ — $ 2,963 Derivative financial instruments $ — $ 22 $ — $ 22 Liabilities Derivative financial instruments $ — $ 38 $ — $ 38 There were no transfers between Levels 1 and 2 within the fair value hierarchy for the three months ended March 31, 2016 and 2015 . Available-for-Sale Investment Securities Investment securities classified as available-for-sale consist of U.S. Treasury securities, U.S. government agency securities and residential mortgage-backed securities. The fair value estimates of investment securities classified as Level 1, consisting of U.S. Treasury and government agency securities, are determined based on quoted market prices for the same securities. The Company classifies all other available-for-sale investment securities as Level 2, the fair value estimates of which are obtained from pricing services, where fair values are estimated using pricing models based on observable market inputs or recent trades of similar securities. The fair value estimates of residential mortgage-backed securities are based on the best information available. This data may consist of observed market prices, broker quotes or discounted cash flow models that incorporate assumptions such as benchmark yields, issuer spreads, prepayment speeds, credit ratings and losses, the priority of which may vary based on availability of information. The Company validates the fair value estimates provided by the pricing services primarily by comparison to valuations obtained through other pricing sources. The Company evaluates pricing variances amongst different pricing sources to ensure that the valuations utilized are reasonable. The Company also corroborates the reasonableness of the fair value estimates with analysis of trends of significant inputs, such as market interest rate curves. The Company further performs due diligence in understanding the procedures and techniques performed by the pricing services to derive fair value estimates. At March 31, 2016 , amounts reported in residential mortgage-backed securities reflect government-rated obligations issued by Fannie Mae, Freddie Mac and Ginnie Mae with a par value of $1.1 billion , a weighted-average coupon of 2.81% and a weighted-average remaining maturity of three years . Derivative Financial Instruments The Company's derivative financial instruments consist of interest rate swaps and foreign exchange forward contracts. These instruments are classified as Level 2 as their fair values are estimated using proprietary pricing models, containing certain assumptions based on readily observable market-based inputs, including interest rate curves, option volatility and foreign currency forward and spot rates. In determining fair values, the pricing models use widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity and the observable market-based inputs. The fair values of the interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments are based on an expectation of future interest rates derived from the observable market interest rate curves. The Company considers collateral and master netting agreements that mitigate credit exposure to counterparties in determining the counterparty credit risk valuation adjustment. The fair values of the currency instruments are valued comparing the contracted forward exchange rate pertaining to the specific contract maturities to the current market exchange rate. The Company validates the fair value estimates of interest rate swaps primarily through comparison to the fair value estimates computed by the counterparties to each of the derivative transactions. The Company evaluates pricing variances amongst different pricing sources to ensure that the valuations utilized are reasonable. The Company also corroborates the reasonableness of the fair value estimates with analysis of trends of significant inputs, such as market interest rate curves. The Company performs due diligence in understanding the impact to any changes to the valuation techniques performed by proprietary pricing models prior to implementation, working closely with the third-party valuation service, and reviews the control objectives of the service at least annually. The Company corroborates the fair value of foreign exchange forward contracts through independent calculation of the fair value estimates. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis The Company also has assets that under certain conditions are subject to measurement at fair value on a non-recurring basis. These assets include those associated with acquired businesses, including goodwill and other intangible assets. For these assets, measurement at fair value in periods subsequent to the initial recognition of the assets is applicable if one or more of the assets is determined to be impaired. During the three months ended March 31, 2016 and 2015 , the Company had no material impairments related to these assets. Financial Instruments Measured at Other Than Fair Value The following tables disclose the estimated fair value of the Company's financial assets and financial liabilities that are not required to be carried at fair value (dollars in millions): Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Carrying Value Balance at March 31, 2016 Assets U.S Treasury securities $ 1 $ — $ — $ 1 $ 1 States and political subdivisions of states — 5 — 5 5 Residential mortgage-backed securities - Agency — 129 — 129 126 Held-to-maturity investment securities $ 1 $ 134 $ — $ 135 $ 132 Cash and cash equivalents $ 12,135 $ — $ — $ 12,135 $ 12,135 Restricted cash $ 1,010 $ — $ — $ 1,010 $ 1,010 Net loan receivables $ — $ — $ 69,473 $ 69,473 $ 68,399 Accrued interest receivables $ — $ 666 $ — $ 666 $ 666 Liabilities Deposits $ — $ 48,775 $ — $ 48,775 $ 48,465 Long-term borrowings - owed to securitization investors $ — $ 15,849 $ 1,131 $ 16,980 $ 16,779 Other long-term borrowings $ — $ 8,444 $ — $ 8,444 $ 7,973 Accrued interest payables $ — $ 172 $ — $ 172 $ 172 Balance at December 31, 2015 Assets U.S Treasury securities $ 1 $ — $ — $ 1 $ 1 States and political subdivisions of states — 7 — 7 7 Residential mortgage-backed securities - Agency — 114 — 114 113 Held-to-maturity investment securities $ 1 $ 121 $ — $ 122 $ 121 Cash and cash equivalents $ 9,572 $ — $ — $ 9,572 $ 9,572 Restricted cash $ 99 $ — $ — $ 99 $ 99 Net loan receivables $ — $ — $ 71,455 $ 71,455 $ 70,516 Accrued interest receivables $ — $ 660 $ — $ 660 $ 660 Liabilities Deposits (1) $ — $ 47,714 $ — $ 47,714 $ 47,531 Long-term borrowings - owed to securitization investors (1) $ — $ 15,634 $ 1,220 $ 16,854 $ 16,735 Other long-term borrowings (1) $ — $ 8,355 $ — $ 8,355 $ 7,915 Accrued interest payables $ — $ 158 $ — $ 158 $ 158 (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information. The fair values of these financial assets and liabilities, which are not carried at fair value on the condensed consolidated statements of financial condition, were determined by applying the fair value provisions discussed herein. The use of different assumptions or estimation techniques may have a material effect on these estimated fair value amounts. The following describes the valuation techniques of these financial instruments measured at other than fair value. Cash and Cash Equivalents The carrying value of cash and cash equivalents approximates fair value due to the low level of risk these assets present to the Company, as well as the relatively liquid nature of these assets, particularly given their short maturities. Restricted Cash The carrying value of restricted cash approximates fair value due to the low level of risk these assets present to the Company, as well as the relatively liquid nature of these assets, particularly given their short maturities. Held-to-Maturity Investment Securities Held-to-maturity investment securities consist of residential mortgage-backed securities issued by agencies and municipal bonds. The fair value of residential mortgage-backed securities included in the held-to-maturity portfolio is estimated similarly to residential mortgage-backed securities carried at fair value on a recurring basis discussed herein. Municipal bonds are valued based on quoted market prices for the same or similar securities. Net Loan Receivables The Company's loan receivables are comprised of credit card and installment loans, including the PCI student loans. Fair value estimates are derived utilizing discounted cash flow analyses, the calculations of which are performed on groupings of loan receivables that are similar in terms of loan type and characteristics. Inputs to the cash flow analysis of each grouping consider recent prepayment and interest accrual trends and leverage forecasted loss estimates. The expected future cash flows, derived through the cash flow analysis, of each grouping are discounted at rates at which similar loans within each grouping could be originated under current market conditions. Significant inputs to the fair value measurement of the loan portfolio are unobservable and, as such, are classified as Level 3. Accrued Interest Receivables The carrying value of accrued interest receivables, which is included in other assets on the condensed consolidated statements of financial condition, approximates fair value as it is due in less than one year. Deposits The carrying values of money market deposits, savings deposits and demand deposits approximate fair value due to the potentially liquid nature of these deposits. For time deposits for which readily available market rates do not exist, fair values are estimated by discounting expected future cash flows using market rates currently offered for deposits with similar remaining maturities. Long-Term Borrowings - Owed to Securitization Investors Fair values of long-term borrowings owed to credit card securitization investors are determined utilizing quoted market prices of the same transactions and, as such, are classified as Level 2. Fair values of long-term borrowings owed to student loan securitization investors are calculated by discounting cash flows using estimated assumptions including, among other things, maturity and market discount rates. A portion of the difference between the carrying value and the fair value of the long-term borrowings owed to student loan securitization investors relates to purchase accounting adjustments recorded in connection with the December 2010 purchase of SLC. Significant inputs to these fair value measurements are unobservable and, as such, are classified as Level 3. Other Long-Term Borrowings Fair values of other long-term borrowings, consisting of subordinated and senior debt, are determined utilizing current observable market prices for those transactions and, as such, are classified as Level 2. A portion of the difference between the carrying value and the fair value of other long-term borrowings relates to the cash premiums paid in connection with the 2012 fiscal year debt exchanges. Accrued Interest Payables The carrying value of accrued interest payables, which is included in accrued expenses and other liabilities on the condensed consolidated statements of financial condition, approximates fair value as it is payable in less than one year.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	Derivatives and Hedging Activities The Company uses derivatives to manage its exposure to various financial risks. The Company does not enter into derivatives for trading or speculative purposes. Certain derivatives used to manage the Company’s exposure to interest rate movements and other identified risks are not designated as hedges and do not qualify for hedge accounting. Derivatives may give rise to counterparty credit risk, which generally is addressed through collateral arrangements as described under the sub-heading "— Collateral Requirements and Credit-Risk Related Contingency Features." The Company enters into derivative transactions with established dealers that meet minimum credit criteria established by the Company. All counterparties must be pre-approved prior to engaging in any transaction with the Company. Counterparties are monitored on a regular basis by the Company to ensure compliance with the Company’s risk policies and limits. In determining the counterparty credit risk valuation adjustment for the fair values of derivatives, the Company considers collateral and legally enforceable master netting agreements that mitigate credit exposure to related counterparties. All derivatives are recorded in other assets at their gross positive fair values and in accrued expenses and other liabilities at their gross negative fair values. See Note 14: Fair Value Measurements and Disclosures for a description of the valuation methodologies of derivatives. Cash collateral posted and held balances are recorded in other assets and deposits, respectively, in the condensed consolidated statements of financial condition. Collateral amounts recorded in the condensed consolidated statements of financial condition are based on the net collateral posted or held position for each applicable legal entity's master netting arrangement with each counterparty. Derivatives Designated as Hedges Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows arising from changes in interest rates, or other types of forecasted transactions, are considered cash flow hedges. Derivatives designated and qualifying as a hedge of the exposure to fluctuations in foreign exchange rates on investments in foreign entities are referred to as net investment hedges. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Cash Flow Hedges The Company uses interest rate swaps to manage its exposure to changes in interest rates related to future cash flows resulting from interest payments on credit card securitized debt and deposits. The Company's outstanding cash flow hedges are for an initial maximum period of five years for securitized debt and seven years for deposits. The derivatives are designated as hedges of the risk of changes in cash flows on the Company's LIBOR or Federal Funds rate-based interest payments and qualify for hedge accounting in accordance with ASC Topic 815, Derivatives and Hedging (“ASC 815”). The effective portion of the change in the fair value of derivatives designated as cash flow hedges is recorded in OCI and is subsequently reclassified into earnings in the period that the hedged forecasted cash flows affect earnings. The ineffective portion of the change in fair value of the derivative, if any, is recognized directly in earnings. Amounts reported in AOCI related to derivatives at March 31, 2016 will be reclassified to interest expense as interest payments are made on certain of the Company's floating-rate securitized debt or deposits. During the next 12 months, the Company estimates it will reclassify $31 million of pretax losses to interest expense related to its derivatives designated as cash flow hedges. Fair Value Hedges The Company is exposed to changes in fair value of certain of its fixed-rate debt obligations due to changes in interest rates. The Company uses interest rate swaps to manage its exposure to changes in fair value of certain fixed-rate senior notes, securitized debt, bank notes and interest-bearing brokered deposits attributable to changes in LIBOR, a benchmark interest rate as defined by ASC 815. These interest rate swaps qualify as fair value hedges in accordance with ASC 815. Changes in both (i) the fair values of the derivatives and (ii) the hedged fixed-rate senior notes, securitized debt, bank notes and interest-bearing brokered deposits relating to the risk being hedged are recorded in interest expense. The changes generally provide substantial offset to one another, with any difference, or ineffectiveness recorded in interest expense. Any basis differences between the fair value and the carrying amount of the hedged item at the inception of the hedging relationship are amortized to interest expense. Derivatives Not Designated as Hedges Foreign Exchange Forward Contracts The Company has foreign exchange forward contracts that are economic hedges and are not designated as accounting hedges. The Company enters into foreign exchange forward contracts to manage foreign currency risk. Changes in the fair value of these contracts are recorded in other income. Interest Rate Swaps The Company may have, from time to time, interest rate swap agreements that are not designated as hedges. Such agreements are not speculative and are also used to manage interest rate risk but are not designated for hedge accounting. Changes in the fair value of these contracts are recorded in other income. The following table summarizes the fair value (including accrued interest) and outstanding notional amounts of derivative instruments and related collateral balances (dollars in millions): March 31, 2016 December 31, 2015 Notional Amount Number of Outstanding Derivative Contracts Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedges Interest rate swaps—cash flow hedge $ 4,100 8 $ — $ 78 $ 4,100 $ — $ 35 Interest rate swaps—fair value hedge $ 4,854 105 58 — $ 4,110 22 3 Derivatives not designated as hedges Foreign exchange forward contracts (1) $ 32 6 — — $ 32 — — Interest rate swap (2) $ 198 1 — — $ 217 — — Total gross derivative assets/liabilities (3) 58 78 22 38 Less: Collateral held/posted (4) (21 ) (63 ) (8 ) (33 ) Total net derivative assets/liabilities $ 37 $ 15 $ 14 $ 5 (1) The foreign exchange forward contracts have notional amounts of EUR 19 million , GBP 7 million and SGD 1 million as of March 31, 2016 , and notional amounts of EUR 19 million , GBP 7 million and SGD 1 million as of December 31, 2015 . (2) Interest rate swaps not designated as hedges do not have associated master netting arrangements. (3) In addition to the derivatives disclosed in the table, the Company enters into forward contracts to purchase when-issued mortgage-backed securities as part of its community reinvestment initiatives. At March 31, 2016 , the Company had one outstanding contract with a notional amount of $36 million and immaterial fair value. At December 31, 2015 , the Company had one outstanding contract with a notional amount of $52 million and immaterial fair value. (4) Collateral amounts, which consist of both cash and investment securities, are limited to the related derivative asset/liability balance and do not include excess collateral received/pledged. The following tables summarize the impact of the derivative instruments on income and OCI and indicates where within the condensed consolidated financial statements such impact is reported (dollars in millions): Amount of Loss Recognized in OCI For the Three Months Ended March 31, Location 2016 2015 Derivatives designated as hedges Interest rate swaps - cash flow/net investment hedges Total loss recognized in OCI after amounts reclassified into earnings, pre-tax OCI $ (43 ) $ (35 ) Total loss recognized in OCI $ (43 ) $ (35 ) Amount of (Loss) Gain Recognized in Income For the Three Months Ended March 31, Location 2016 2015 Derivatives designated as hedges Interest rate swaps - cash flow hedges Amount reclassified from OCI into income Interest Expense $ (9 ) $ (12 ) Total amount reclassified from OCI into income (9 ) (12 ) Interest rate swaps - fair value hedges Adjustments - ineffectiveness 31 5 Adjustments - other 9 8 Gain on interest rate swaps Interest Expense 40 13 Adjustments - ineffectiveness (29 ) (3 ) Adjustments - other (2 ) (1 ) Loss on hedged item Interest Expense (31 ) (4 ) Total loss on derivatives designated as hedges recognized in income $ — $ (3 ) Derivatives not designated as hedges Total (loss) gain on derivatives not designated as hedges recognized in income (1) Other Income $ (1 ) $ 49 (1) Amount as of March 31, 2015 includes $2 million gain on forward delivery contracts and $44 million gain on interest rate lock commitments related to the mortgage loan business that was closed during 2015. See Note 2: Business Dispositions. Collateral Requirements and Credit-Risk Related Contingency Features The Company has master netting arrangements and minimum collateral posting thresholds with its counterparties for its fair value and cash flow hedge interest rate swaps, foreign exchange forward contracts and forward delivery contracts. The Company has not sought a legal opinion in relation to the enforceability of its master netting arrangements and, as such, does not report any of these positions on a net basis. Collateral is required by either the Company or its subsidiaries or the counterparty depending on the net fair value position of these derivatives held with that counterparty. The Company may also be required to post collateral with a counterparty for its fair value and cash flow hedge interest rate swaps depending on the credit rating it or Discover Bank receives from specified major credit rating agencies. Collateral receivable or payable amounts are not offset against the fair value of these derivatives, but are recorded separately in other assets or deposits. As of March 31, 2016 , DFS had a right to reclaim $4 million of cash collateral that had been posted (net of amounts required to be posted by the counterparty) because the credit rating of the Company did not meet specified thresholds. At March 31, 2016 , Discover Bank’s credit rating met specified thresholds set by its counterparties. However, if its credit rating is reduced by one ratings notch, Discover Bank would be required to post additional collateral, which would have been $69 million as of March 31, 2016 . The Company also has agreements with certain of its derivative counterparties that contain a provision where if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations.

Segment Disclosures

Segment Disclosures	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Segment Disclosures	Segment Disclosures The Company’s business activities are managed in two segments: Direct Banking and Payment Services. • Direct Banking: The Direct Banking segment includes Discover-branded credit cards issued to individuals on the Discover Network and other consumer products and services, including private student loans, personal loans, home equity loans, and other consumer lending and deposit products. The majority of Direct Banking revenues relate to interest income earned on the segment's loan products. Additionally, the Company’s credit card products generate substantially all revenues related to discount and interchange, protection products and loan fee income. • Payment Services: The Payment Services segment includes PULSE, an automated teller machine, debit and electronic funds transfer network; Diners Club, a global payments network; and the Company’s Network Partners business, which provides payment transaction processing and settlement services on the Discover Network. The majority of Payment Services revenues relate to transaction processing revenue from PULSE and royalty and licensee revenue (included in other income) from Diners Club. The business segment reporting provided to and used by the Company’s chief operating decision maker is prepared using the following principles and allocation conventions: • The Company aggregates operating segments when determining reportable segments. • Corporate overhead is not allocated between segments; all corporate overhead is included in the Direct Banking segment. • Through its operation of the Discover Network, the Direct Banking segment incurs fixed marketing, servicing and infrastructure costs that are not specifically allocated among the segments, with the exception of an allocation of direct and incremental costs driven by the Company's Payment Services segment. • The assets of the Company are not allocated among the operating segments in the information reviewed by the Company’s chief operating decision maker. • The revenues of each segment are derived from external sources. The segments do not earn revenue from intercompany sources. • Income taxes are not specifically allocated between the operating segments in the information reviewed by the Company’s chief operating decision maker. The following table presents segment data (dollars in millions): Direct Banking Payment Services Total For the Three Months Ended March 31, 2016 Interest income Credit card loans $ 1,733 $ — $ 1,733 Private student loans 107 — 107 PCI student loans 49 — 49 Personal loans 167 — 167 Other 28 — 28 Total interest income 2,084 — 2,084 Interest expense 334 — 334 Net interest income 1,750 — 1,750 Provision for loan losses 423 1 424 Other income 406 68 474 Other expense 851 35 886 Income before income tax expense $ 882 $ 32 $ 914 For the Three Months Ended March 31, 2015 Interest income Credit card loans $ 1,606 $ — $ 1,606 Private student loans 90 — 90 PCI student loans 60 — 60 Personal loans 152 — 152 Other 21 — 21 Total interest income 1,929 — 1,929 Interest expense 300 — 300 Net interest income 1,629 — 1,629 Provision for loan losses 388 2 390 Other income 468 74 542 Other expense 828 45 873 Income before income tax expense $ 881 $ 27 $ 908

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated events and transactions that have occurred subsequent to March 31, 2016 and determined that other than the matters disclosed in Note 9: Income Taxes, there were no subsequent events that would require recognition or disclosure in the condensed consolidated financial statements.

Background and Basis of Prese25

Background and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. In the opinion of management, the financial statements reflect all adjustments which are necessary for a fair presentation of the results for the interim period. All such adjustments are of a normal, recurring nature.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and related disclosures. These estimates are based on information available as of the date of the condensed consolidated financial statements. The Company believes that the estimates used in the preparation of the condensed consolidated financial statements are reasonable. Actual results could differ from these estimates.
Fair Value of Financial Instruments	The fair values of these financial assets and liabilities, which are not carried at fair value on the condensed consolidated statements of financial condition, were determined by applying the fair value provisions discussed herein. The use of different assumptions or estimation techniques may have a material effect on these estimated fair value amounts. The following describes the valuation techniques of these financial instruments measured at other than fair value. Cash and Cash Equivalents The carrying value of cash and cash equivalents approximates fair value due to the low level of risk these assets present to the Company, as well as the relatively liquid nature of these assets, particularly given their short maturities. Restricted Cash The carrying value of restricted cash approximates fair value due to the low level of risk these assets present to the Company, as well as the relatively liquid nature of these assets, particularly given their short maturities. Held-to-Maturity Investment Securities Held-to-maturity investment securities consist of residential mortgage-backed securities issued by agencies and municipal bonds. The fair value of residential mortgage-backed securities included in the held-to-maturity portfolio is estimated similarly to residential mortgage-backed securities carried at fair value on a recurring basis discussed herein. Municipal bonds are valued based on quoted market prices for the same or similar securities. Net Loan Receivables The Company's loan receivables are comprised of credit card and installment loans, including the PCI student loans. Fair value estimates are derived utilizing discounted cash flow analyses, the calculations of which are performed on groupings of loan receivables that are similar in terms of loan type and characteristics. Inputs to the cash flow analysis of each grouping consider recent prepayment and interest accrual trends and leverage forecasted loss estimates. The expected future cash flows, derived through the cash flow analysis, of each grouping are discounted at rates at which similar loans within each grouping could be originated under current market conditions. Significant inputs to the fair value measurement of the loan portfolio are unobservable and, as such, are classified as Level 3. Accrued Interest Receivables The carrying value of accrued interest receivables, which is included in other assets on the condensed consolidated statements of financial condition, approximates fair value as it is due in less than one year. Deposits The carrying values of money market deposits, savings deposits and demand deposits approximate fair value due to the potentially liquid nature of these deposits. For time deposits for which readily available market rates do not exist, fair values are estimated by discounting expected future cash flows using market rates currently offered for deposits with similar remaining maturities. Long-Term Borrowings - Owed to Securitization Investors Fair values of long-term borrowings owed to credit card securitization investors are determined utilizing quoted market prices of the same transactions and, as such, are classified as Level 2. Fair values of long-term borrowings owed to student loan securitization investors are calculated by discounting cash flows using estimated assumptions including, among other things, maturity and market discount rates. A portion of the difference between the carrying value and the fair value of the long-term borrowings owed to student loan securitization investors relates to purchase accounting adjustments recorded in connection with the December 2010 purchase of SLC. Significant inputs to these fair value measurements are unobservable and, as such, are classified as Level 3. Other Long-Term Borrowings Fair values of other long-term borrowings, consisting of subordinated and senior debt, are determined utilizing current observable market prices for those transactions and, as such, are classified as Level 2. A portion of the difference between the carrying value and the fair value of other long-term borrowings relates to the cash premiums paid in connection with the 2012 fiscal year debt exchanges. Accrued Interest Payables The carrying value of accrued interest payables, which is included in accrued expenses and other liabilities on the condensed consolidated statements of financial condition, approximates fair value as it is payable in less than one year.

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of Investment Securities	The Company’s investment securities consist of the following (dollars in millions): March 31, December 31, U.S. Treasury securities (1) $ 1,181 $ 1,273 U.S. government agency securities 492 494 States and political subdivisions of states 5 7 Residential mortgage-backed securities - Agency (2) 1,278 1,310 Total investment securities $ 2,956 $ 3,084 (1) Includes $20 million and $7 million of U.S. Treasury securities pledged as swap collateral in lieu of cash as of March 31, 2016 and December 31, 2015 , respectively. (2) Consists of residential mortgage-backed securities issued by Fannie Mae, Freddie Mac and Ginnie Mae.
Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value	The amortized cost, gross unrealized gains and losses, and fair value of available-for-sale and held-to-maturity investment securities are as follows (dollars in millions): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value At March 31, 2016 Available-for-Sale Investment Securities (1) U.S. Treasury securities $ 1,177 $ 3 $ — $ 1,180 U.S. government agency securities 491 1 — 492 Residential mortgage-backed securities - Agency 1,134 18 — 1,152 Total available-for-sale investment securities $ 2,802 $ 22 $ — $ 2,824 Held-to-Maturity Investment Securities (2) U.S. Treasury securities (3) $ 1 $ — $ — $ 1 States and political subdivisions of states 5 — — 5 Residential mortgage-backed securities - Agency (4) 126 3 — 129 Total held-to-maturity investment securities $ 132 $ 3 $ — $ 135 At December 31, 2015 Available-for-Sale Investment Securities (1) U.S. Treasury securities $ 1,277 $ 1 $ (6 ) $ 1,272 U.S. government agency securities 492 2 — 494 Residential mortgage-backed securities - Agency 1,195 6 (4 ) 1,197 Total available-for-sale investment securities $ 2,964 $ 9 $ (10 ) $ 2,963 Held-to-Maturity Investment Securities (2) U.S. Treasury securities (3) $ 1 $ — $ — $ 1 States and political subdivisions of states 7 — — 7 Residential mortgage-backed securities - Agency (4) 113 1 — 114 Total held-to-maturity investment securities $ 121 $ 1 $ — $ 122 (1) Available-for-sale investment securities are reported at fair value. (2) Held-to-maturity investment securities are reported at amortized cost. (3) Amount represents securities pledged as collateral to a government-related merchant for which transaction settlement occurs beyond the normal 24-hour period. (4) Amounts represent residential mortgage-backed securities that were classified as held-to-maturity as they were entered into as a part of the Company's community reinvestment initiatives.
Schedule of Fair Value of Securities in a Continuous Unrealized Loss Position for Less Than 12 Months and More Than 12 Months	The following table provides information about investment securities with aggregate gross unrealized losses and the length of time that individual investment securities have been in a continuous unrealized loss position (dollars in millions): Number of Securities in a Loss Position Less than 12 months More than 12 months Fair Value Unrealized Losses Fair Value Unrealized Losses At December 31, 2015 Available-for-Sale Investment Securities U.S. Treasury securities 1 $ 670 $ (6 ) $ — $ — Residential mortgage-backed securities - Agency 15 $ 486 $ (4 ) $ — $ —
Schedule of Proceeds, Recognized Gains and Losses and Net Unrealized Gains and Losses	The following table provides information about proceeds from sales, recognized gains and losses and net unrealized gains and losses on available-for-sale securities (dollars in millions): For the Three Months Ended March 31, 2016 2015 Proceeds from the sales of available-for-sale investment securities $ — $ 899 Gain on sales of available-for-sale investment securities $ — $ 8 Net unrealized gain recorded in other comprehensive income, before-tax $ 23 $ — Net unrealized gain recorded in other comprehensive income, after-tax $ 14 $ —
Schedule of Maturities of Available-for-Sale Debt Securities and Held-to-Maturity Debt Securities	Maturities of available-for-sale debt securities and held-to-maturity debt securities are provided in the table below (dollars in millions): One Year or Less After One Year Through Five Years After Five Years Through Ten Years After Ten Years Total At March 31, 2016 Available-for-Sale Investment Securities—Amortized Cost U.S. Treasury securities $ 500 $ 677 $ — $ — $ 1,177 U.S. government agency securities 491 — — — 491 Residential mortgage-backed securities - Agency — — 359 775 1,134 Total available-for-sale investment securities $ 991 $ 677 $ 359 $ 775 $ 2,802 Held-to-Maturity Investment Securities—Amortized Cost U.S. Treasury securities $ 1 $ — $ — $ — $ 1 State and political subdivisions of states — — — 5 5 Residential mortgage-backed securities - Agency — — — 126 126 Total held-to-maturity investment securities $ 1 $ — $ — $ 131 $ 132 Available-for-Sale Investment Securities—Fair Values U.S. Treasury securities $ 501 $ 679 $ — $ — $ 1,180 U.S. government agency securities 492 — — — 492 Residential mortgage-backed securities - Agency — — 363 789 1,152 Total available-for-sale investment securities $ 993 $ 679 $ 363 $ 789 $ 2,824 Held-to-Maturity Investment Securities—Fair Values U.S. Treasury securities $ 1 $ — $ — $ — $ 1 State and political subdivisions of states — — — 5 5 Residential mortgage-backed securities - Agency — — — 129 129 Total held-to-maturity investment securities $ 1 $ — $ — $ 134 $ 135

Loan Receivables (Tables)

Loan Receivables (Tables)	3 Months Ended
	Mar. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Schedule of Loan Receivables	The Company's classes of receivables within the three portfolio segments are depicted in the table below (dollars in millions): March 31, December 31, Loan receivables Credit card loans (1) $ 55,620 $ 57,896 Other loans Personal loans 5,534 5,490 Private student loans 5,949 5,647 Other 252 236 Total other loans 11,735 11,373 Purchased credit-impaired loans (2) 2,965 3,116 Total loan receivables 70,320 72,385 Allowance for loan losses (1,921 ) (1,869 ) Net loan receivables $ 68,399 $ 70,516 (1) Amounts include $20.9 billion and $21.6 billion underlying investors’ interest in trust debt at March 31, 2016 and December 31, 2015 and $6.2 billion and $7.2 billion in seller's interest at March 31, 2016 and December 31, 2015 , respectively. See Note 5: Credit Card and Student Loan Securitization Activities for further information. (2) Amounts include $1.6 billion and $1.7 billion of loans pledged as collateral against the notes issued from the Student Loan Corporation ("SLC") securitization trusts at March 31, 2016 and December 31, 2015 , respectively. See Note 5: Credit Card and Student Loan Securitization Activities.
Schedule of Delinquent and Non-Accruing Loans	Information related to the delinquent and non-accruing loans in the Company’s loan portfolio is shown below by each class of loan receivables except for PCI student loans, which is shown under the heading “— Purchased Credit-Impaired Loans” (dollars in millions): 30-89 Days Delinquent 90 or More Days Delinquent Total Past Due 90 or More Days Delinquent and Accruing Total Non-accruing (1) At March 31, 2016 Credit card loans (2) $ 454 $ 480 $ 934 $ 427 $ 190 Other loans Personal loans (3) 40 14 54 13 6 Private student loans (excluding PCI) (4) 78 36 114 36 — Other 2 1 3 — 20 Total other loans (excluding PCI) 120 51 171 49 26 Total loan receivables (excluding PCI) $ 574 $ 531 $ 1,105 $ 476 $ 216 At December 31, 2015 Credit card loans (2) $ 505 $ 490 $ 995 $ 422 $ 198 Other loans Personal loans (3) 34 15 49 13 6 Private student loans (excluding PCI) (4) 84 24 108 25 — Other — 1 1 — 20 Total other loans (excluding PCI) 118 40 158 38 26 Total loan receivables (excluding PCI) $ 623 $ 530 $ 1,153 $ 460 $ 224 (1) The Company estimates that the gross interest income that would have been recorded in accordance with the original terms of non-accruing credit card loans was $8 million and $7 million for the three months ended March 31, 2016 and 2015 , respectively. The Company does not separately track the amount of gross interest income that would have been recorded in accordance with the original terms of loans. This amount was estimated based on customers' current balances and most recent interest rates. (2) Credit card loans that are 90 or more days delinquent and accruing interest include $44 million and $42 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 , respectively. (3) Personal loans that are 90 or more days delinquent and accruing interest include $4 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 . (4) Private student loans that are 90 or more days delinquent and accruing interest include $3 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015 .
Schedule of Net Charge-offs	Information related to the net charge-offs in the Company's loan portfolio is shown below by each class of loan receivables except for PCI student loans, which is shown under the heading "— Purchased Credit-Impaired Loans" (dollars in millions): For the Three Months Ended March 31, 2016 2015 Net Net Charge-off Net Net Charge-off Credit card loans $ 326 2.34 % $ 319 2.40 % Other loans Personal loans 34 2.45 % 28 2.22 % Private student loans (excluding PCI) 12 0.85 % 13 1.03 % Total other loans (excluding PCI) 46 1.59 % 41 1.58 % Net charge-offs as a percentage of total loans (excluding PCI) $ 372 2.21 % $ 360 2.26 % Net charge-offs as a percentage of total loans (including PCI) $ 372 2.11 % $ 360 2.14 %
Schedule of Credit Risk Profile by FICO Score	The following table provides the most recent FICO scores available for the Company’s customers as a percentage of each class of loan receivables: Credit Risk Profile 660 and Above Less than 660 or No Score At March 31, 2016 Credit card loans 82 % 18 % Personal loans 96 % 4 % Private student loans (excluding PCI) (1) 96 % 4 % At December 31, 2015 Credit card loans 83 % 17 % Personal loans 96 % 4 % Private student loans (excluding PCI) (1) 96 % 4 % (1) PCI loans are discussed under the heading "— Purchased Credit-Impaired Loans."
Schedule of Changes in the Allowance for Loan Losses	The following tables provide changes in the Company’s allowance for loan losses (dollars in millions): For the Three Months Ended March 31, 2016 Credit Card Personal Loans Student Loans (1) Other Total Balance at beginning of period $ 1,554 $ 155 $ 143 $ 17 $ 1,869 Additions Provision for loan losses 362 44 17 1 424 Deductions Charge-offs (439 ) (39 ) (15 ) — (493 ) Recoveries 113 5 3 — 121 Net charge-offs (326 ) (34 ) (12 ) — (372 ) Balance at end of period $ 1,590 $ 165 $ 148 $ 18 $ 1,921 For the Three Months Ended March 31, 2015 Credit Card Personal Loans Student Loans (1) Other Total Balance at beginning of period $ 1,474 $ 120 $ 135 $ 17 $ 1,746 Additions Provision for loan losses 337 31 20 2 390 Deductions Charge-offs (428 ) (31 ) (15 ) — (474 ) Recoveries 109 3 2 — 114 Net charge-offs (319 ) (28 ) (13 ) — (360 ) Balance at end of period $ 1,492 $ 123 $ 142 $ 19 $ 1,776 (1) Includes both PCI and non-PCI private student loans.
Schedule of Net Charge-offs of Interest and Fee Revenues on Loan Receivables	Net charge-offs of principal are recorded against the allowance for loan losses, as shown in the preceding table. Information regarding net charge-offs of interest and fee revenues on credit card and other loans is as follows (dollars in millions): For the Three Months Ended March 31, 2016 2015 Interest and fees accrued subsequently charged off, net of recoveries (recorded as a reduction of interest income) $ 69 $ 75 Fees accrued subsequently charged off, net of recoveries (recorded as a reduction to other income) $ 17 $ 20
Schedule of Allowance for Loan Losses and Recorded Investment in its Loan Portfolio by Impairment Methodology	The following tables provide additional detail of the Company’s allowance for loan losses and recorded investment in its loan portfolio by impairment methodology (dollars in millions): Credit Card Personal Loans Student Loans (3) Other Loans (4) Total At March 31, 2016 Allowance for loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 1,430 $ 149 $ 96 $ 1 $ 1,676 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 160 16 16 17 209 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 36 — 36 Total allowance for loan losses $ 1,590 $ 165 $ 148 $ 18 $ 1,921 Recorded investment in loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 54,600 $ 5,464 $ 5,896 $ 194 $ 66,154 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 1,020 70 53 58 1,201 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 2,965 — 2,965 Total recorded investment $ 55,620 $ 5,534 $ 8,914 $ 252 $ 70,320 At December 31, 2015 Allowance for loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 1,394 $ 140 $ 92 $ 1 $ 1,627 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 160 15 15 16 206 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 36 — 36 Total allowance for loan losses $ 1,554 $ 155 $ 143 $ 17 $ 1,869 Recorded investment in loans evaluated for impairment as Collectively evaluated for impairment in accordance with ASC 450-20 $ 56,877 $ 5,422 $ 5,599 $ 179 $ 68,077 Evaluated for impairment in accordance with ASC 310-10-35 (1)(2) 1,019 68 48 57 1,192 Acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30 — — 3,116 — 3,116 Total recorded investment $ 57,896 $ 5,490 $ 8,763 $ 236 $ 72,385 (1) Loan receivables evaluated for impairment in accordance with Accounting Standards Codification ("ASC") 310-10-35 include credit card loans, personal loans and student loans collectively evaluated for impairment in accordance with ASC Subtopic 310-40, Receivables, which consists of modified loans accounted for as troubled debt restructurings. Other loans are individually evaluated for impairment and generally do not represent troubled debt restructurings. (2) The unpaid principal balance of credit card loans was $873 million and $869 million at March 31, 2016 and December 31, 2015 , respectively. The unpaid principal balance of personal loans was $69 million and $67 million at March 31, 2016 and December 31, 2015 , respectively. The unpaid principal balance of student loans was $52 million and $47 million at March 31, 2016 and December 31, 2015 , respectively. All loans accounted for as troubled debt restructurings have a related allowance for loan losses. (3) Includes both PCI and non-PCI private student loans. (4) Certain other loans, including non-performing Diners Club licensee loans, are individually evaluated for impairment.
Schedule of Troubled Debt Restructurings	Additional information about modified loans classified as troubled debt restructurings is shown below (dollars in millions): Average recorded investment in loans Interest income recognized during period loans were impaired (1) Gross interest income that would have been recorded with original terms (2) For the Three Months Ended March 31, 2016 Credit card loans Modified credit card loans (3) $ 274 $ 12 $ 1 Internal programs $ 464 $ 3 $ 16 External programs $ 283 $ 5 $ 3 Personal loans $ 69 $ 2 $ 1 Private student loans $ 50 $ 1 N/A For the Three Months Ended March 31, 2015 Credit card loans Modified credit card loans (3) $ 255 $ 11 $ 1 Internal programs $ 452 $ 3 $ 15 External programs $ 323 $ 6 $ 3 Personal loans $ 57 $ 2 $ 1 Private student loans $ 40 $ 1 N/A (1) The Company does not separately track interest income on loans in modification programs. Amounts shown are estimated by applying an average interest rate to the average loans in the various modification programs. (2) The Company does not separately track the amount of gross interest income that would have been recorded if the loans in modification programs had not been restructured and interest had instead been recorded in accordance with the original terms. Amounts shown are estimated by applying the difference between the average interest rate earned on non-impaired loans and the average interest rate earned on loans in the modification programs to the average loans in the modification programs. (3) This balance is considered impaired, but is excluded from the internal and external program amounts reflected in this table. Represents credit card loans that were modified in troubled debt restructurings, but are no longer enrolled in troubled debt restructuring program due to noncompliance with the terms of the modification or successful completion of a program.
Schedule of Loans That Entered a Modification Program During the Period	The following table provides information on loans that entered a loan modification program during the period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Number of Accounts Balances Number of Accounts Balances Accounts that entered a loan modification program during the period Credit card loans Internal programs 14,967 $ 96 13,243 $ 86 External programs 7,317 $ 39 7,617 $ 39 Personal loans 1,061 $ 12 986 $ 12 Private student loans 452 $ 8 469 $ 7
Schedule of Troubled Debt Restructurings That Subsequently Defaulted	The following table presents the carrying value of loans that experienced a payment default during the period that had been modified in a troubled debt restructuring during the 15 months preceding the end of each period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Number of Accounts Aggregated Outstanding Balances Upon Default Number of Accounts Aggregated Outstanding Balances Upon Default Troubled debt restructurings that subsequently defaulted Credit card loans Internal programs (1)(2) 3,001 $ 18 3,176 $ 20 External programs (1)(2) 1,699 $ 7 1,643 $ 7 Personal loans (2) 158 $ 2 151 $ 2 Private student loans (3) 197 $ 3 305 $ 4 (1) The outstanding balance upon default is the loan balance at the end of the month prior to default. Terms revert back to the pre-modification terms for customers who default from a temporary program and charging privileges remain revoked in most cases. (2) A customer defaults from a modification program after two consecutive missed payments. (3) Student loan defaults have been defined as loans that are 60 or more days delinquent.
Schedule of Changes in Accretable Yield for the Acquired Loans	The following table provides changes in accretable yield for the acquired loans during each period (dollars in millions): For the Three Months Ended March 31, 2016 2015 Balance at beginning of period $ 965 $ 1,341 Accretion into interest income (49 ) (59 ) Other changes in expected cash flows — (101 ) Balance at end of period $ 916 $ 1,181

Credit Card and Student Loan 28

Credit Card and Student Loan Securitization Activities (Tables)	3 Months Ended
	Mar. 31, 2016
Variable Interest Entities Disclosure [Abstract]
Schedule of Restricted Credit Card Securitized Assets [Text Block]	The carrying values of these restricted assets, which are presented on the Company’s condensed consolidated statements of financial condition as relating to securitization activities, are shown in the table below (dollars in millions): March 31, December 31, Restricted cash $ 921 $ 19 Investors’ interests held by third-party investors 15,725 15,625 Investors’ interests held by wholly-owned subsidiaries of Discover Bank 5,199 6,017 Seller’s interest 6,241 7,231 Loan receivables (1) 27,165 28,873 Allowance for loan losses allocated to securitized loan receivables (1) (783 ) (783 ) Net loan receivables 26,382 28,090 Other (2) 6 5 Carrying value of assets of consolidated variable interest entities $ 27,309 $ 28,114 (1) The Company maintains its allowance for loan losses at an amount sufficient to absorb probable losses inherent in all loan receivables, which includes all loan receivables in the trusts. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company’s balance sheet in accordance with GAAP. (2) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.
Schedule of Investors' Interests and Related Excess Spreads	The table below provides information concerning investors’ interests and related excess spread (dollars in millions): At March 31, 2016 Investors’ Interests (1) Number of Series Outstanding 3-Month Rolling Average Excess Spread Discover Card Execution Note Trust (DiscoverSeries notes) $ 20,924 36 13.55 % (1) Investors’ interests include third-party interests and subordinated interests held by wholly-owned subsidiaries of Discover Bank.
Schedule of Restricted Student Loan Securitized Assets [Text Block]	The carrying values of these restricted assets, which are presented on the Company’s condensed consolidated statements of financial condition as relating to securitization activities, are shown in the table below (dollars in millions): March 31, December 31, Restricted cash $ 89 $ 80 Student loan receivables (1) 1,596 1,678 Allowance for loan losses allocated to securitized loan receivables (1) (28 ) (28 ) Net student loan receivables 1,568 1,650 Carrying value of assets of consolidated variable interest entities $ 1,657 $ 1,730 (1) The Company maintains its allowance for loan losses on PCI loans sufficient to absorb probable decreases in cash flows that were previously expected. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company's balance sheet in accordance with GAAP.

Deposits (Tables)

Deposits (Tables)	3 Months Ended
	Mar. 31, 2016
Deposits [Abstract]
Schedule of Interest Bearing Deposit Accounts	The following table provides a summary of interest-bearing deposit accounts (dollars in millions): March 31, December 31, Certificates of deposit in amounts less than $100,000 (1) $ 19,728 $ 20,491 Certificates of deposit in amounts $100,000 or greater (2) 5,516 5,228 Savings deposits, including money market deposit accounts 22,811 21,375 Total interest-bearing deposits (1) $ 48,055 $ 47,094 (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information. (2) Includes $1.2 billion and $1.1 billion in certificates of deposit greater than $250,000, the Federal Deposit Insurance Corporation ("FDIC") insurance limit, as of March 31, 2016 and December 31, 2015 , respectively.
Schedule of $100,000 or More Certificates of Deposit Maturities	The following table summarizes certificates of deposit in amounts of $100,000 or greater by contractual maturity (dollars in millions): Maturity Period March 31, 2016 Three months or less $ 530 Over three months through six months 742 Over six months through twelve months 1,536 Over twelve months 2,708 Total $ 5,516
Schedule of Certificates of Deposit Maturities	The following table summarizes certificates of deposit maturing over the remainder of this year, over each of the next four years, and thereafter (dollars in millions): Year March 31, 2016 2016 $ 8,335 2017 6,792 2018 3,607 2019 1,966 2020 1,938 Thereafter 2,606 Total $ 25,244

Long-Term Borrowings (Tables)

Long-Term Borrowings (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-Term Borrowings and Weighted Average Interest Rates	Long-term borrowings consist of borrowings having original maturities of one year or more. The following table provides a summary of the Company’s long-term borrowings and weighted-average interest rates on outstanding balances (dollars in millions): March 31, 2016 December 31, 2015 Maturity Interest Weighted-Average Interest Rate Outstanding Amount Outstanding Amount Securitized Debt Fixed-rate asset-backed securities (1)(8) 2016 - 2020 1.04% - 5.65% 2.05% $ 9,268 $ 9,152 Floating-rate asset-backed securities (2)(3)(8) 2016 - 2019 0.62% - 0.89% 0.79% 6,441 6,440 Total Discover Card Master Trust I and Discover Card Execution Note Trust (8) 15,709 15,592 Floating-rate asset-backed securities (4)(5)(6)(7) 2031 - 2042 0.79% - 4.25% 2.21% 1,070 1,143 Total SLC Private Student Loan Trusts 1,070 1,143 Total long-term borrowings - owed to securitization investors (8) 16,779 16,735 Discover Financial Services (Parent Company) Fixed-rate senior notes (1)(8) 2017 - 2025 3.75%-10.25% 4.75% 2,073 2,066 Fixed-rate retail notes (8) 2021 - 2028 3.00% - 4.40% 3.94% 77 39 Discover Bank Fixed-rate senior bank notes (1)(8) 2018 - 2026 2.00% - 4.25% 3.16% 5,128 5,115 Fixed-rate subordinated bank notes (8) 2019 - 2020 7.00% - 8.70% 7.49% 695 695 Total long-term borrowings (8) $ 24,752 $ 24,650 (1) The Company uses interest rate swaps to hedge portions of these long-term borrowings against changes in fair value attributable to changes in London Interbank Offered Rate (“LIBOR”). Use of these interest rate swaps impacts carrying value of the debt. (2) Discover Card Execution Note Trust floating-rate asset-backed securities include issuances with the following interest rate terms: 1-month LIBOR + 18 to 45 basis points and 3-month LIBOR + 20 basis points as of March 31, 2016 . (3) The Company uses interest rate swaps to manage its exposure to changes in interest rates related to future cash flows resulting from interest payments on a portion of these long-term borrowings. There is no impact on debt carrying value from use of these interest rate swaps. See Note 15: Derivatives and Hedging Activities. (4) SLC Private Student Loan Trusts floating-rate asset-backed securities include issuances with the following interest rate terms: 3-month LIBOR + 17 to 45 basis points , Prime rate + 75 to 100 basis points and 1-month LIBOR + 350 basis points as of March 31, 2016 . (5) The Company acquired an interest rate swap related to the securitized debt assumed in the SLC transaction. The swap does not qualify for hedge accounting and has no impact on debt carrying value. See Note 15: Derivatives and Hedging Activities. (6) Repayment of this debt is dependent upon the timing of principal and interest payments on the underlying student loans. The dates shown represent final maturity dates. (7) Includes $302 million of senior notes maturing in 2031, $621 million of senior and subordinated notes maturing in 2036 and $147 million of senior notes maturing in 2042 as of March 31, 2016 . (8) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.
Schedule of Long-Term Borrowings Maturities	The following table summarizes long-term borrowings maturing over the remainder of this year, over each of the next four years, and thereafter (dollars in millions): Year March 31, 2016 2016 $ 2,150 2017 5,099 2018 5,273 2019 4,270 2020 3,094 Thereafter 4,866 Total $ 24,752

Accumulated Other Comprehensi31

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Changes in Accumulated Other Comprehensive Income (Loss)	Changes in each component of accumulated other comprehensive income (loss) ("AOCI") were as follows (dollars in millions): Unrealized Gain on Available-for-Sale Investment Securities, Net of Tax Loss on Cash Flow Hedges, Net of Tax Pension Plan Loss, Net of Tax AOCI For the Three Months Ended March 31, 2016 Balance at December 31, 2015 $ — $ (20 ) $ (140 ) $ (160 ) Net change 14 (26 ) — (12 ) Balance at March 31, 2016 $ 14 $ (46 ) $ (140 ) $ (172 ) For the Three Months Ended March 31, 2015 Balance at December 31, 2014 $ 23 $ (7 ) $ (154 ) $ (138 ) Net change — (23 ) — (23 ) Balance at March 31, 2015 $ 23 $ (30 ) $ (154 ) $ (161 )
Schedule of Other Comprehensive Income Before Reclassifications and Amounts Reclassified from AOCI	The table below presents each component of other comprehensive income (loss) ("OCI") before reclassifications and amounts reclassified from AOCI for each component of OCI before- and after-tax (dollars in millions): Before Tax Tax (Expense) Benefit Net of Tax For the Three Months Ended March 31, 2016 Available-for-Sale Investment Securities Net unrealized holding gain arising during the period $ 23 $ (9 ) $ 14 Amounts reclassified from AOCI — — — Net change $ 23 $ (9 ) $ 14 Cash Flow Hedges Net unrealized loss arising during the period $ (52 ) $ 21 $ (31 ) Amounts reclassified from AOCI 9 (4 ) 5 Net change $ (43 ) $ 17 $ (26 ) For the Three Months Ended March 31, 2015 Available-for-Sale Investment Securities Net unrealized holding gain arising during the period $ 8 $ (3 ) $ 5 Amounts reclassified from AOCI (8 ) 3 (5 ) Net change $ — $ — $ — Cash Flow Hedges Net unrealized loss arising during the period $ (47 ) $ 17 $ (30 ) Amounts reclassified from AOCI 12 (5 ) 7 Net change $ (35 ) $ 12 $ (23 )

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Calculation	The following table presents the calculation of the Company's effective income tax rate (dollars in millions, except effective income tax rate): For the Three Months Ended March 31, 2016 2015 Income before income tax expense $ 914 $ 908 Income tax expense $ 339 $ 322 Effective income tax rate 37.1 % 35.5 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule of Basic and Diluted EPS	The following table presents the calculation of basic and diluted earnings per share ("EPS") (in millions, except per share amounts): For the Three Months Ended March 31, 2016 2015 Numerator Net income $ 575 $ 586 Preferred stock dividends (9 ) (9 ) Net income available to common stockholders 566 577 Income allocated to participating securities (4 ) (4 ) Net income allocated to common stockholders $ 562 $ 573 Denominator Weighted-average shares of common stock outstanding 417 448 Basic earnings per common share $ 1.35 $ 1.28 Diluted earnings per common share $ 1.35 $ 1.28

Capital Adequacy (Tables)

Capital Adequacy (Tables)	3 Months Ended
	Mar. 31, 2016
Regulatory Capital Requirements [Abstract]
Schedule of Minimum and Well-Capitalized Requirements	The following table shows the actual capital amounts and ratios of the Company and Discover Bank and comparisons of each to the regulatory minimum and “well-capitalized” requirements (dollars in millions): Actual Minimum Capital Requirements Capital Requirements To Be Classified as Well-Capitalized Amount Ratio Amount Ratio Amount Ratio March 31, 2016 Total capital (to risk-weighted assets) Discover Financial Services $ 12,463 16.8 % $ 5,936 ≥8.0% $ 7,421 ≥10.0% Discover Bank $ 12,008 16.4 % $ 5,876 ≥8.0% $ 7,345 ≥10.0% Tier 1 capital (to risk-weighted assets) Discover Financial Services $ 11,153 15.0 % $ 4,452 ≥6.0% $ 5,936 ≥8.0% Discover Bank $ 10,061 13.7 % $ 4,407 ≥6.0% $ 5,876 ≥8.0% Tier 1 capital (to average assets) Discover Financial Services $ 11,153 12.8 % $ 3,493 ≥4.0% $ 4,366 ≥5.0% Discover Bank $ 10,061 11.6 % $ 3,459 ≥4.0% $ 4,323 ≥5.0% CET1 capital (to risk-weighted assets) (Basel III transition) Discover Financial Services $ 10,593 14.3 % $ 3,339 ≥4.5% $ 4,823 ≥6.5% Discover Bank $ 10,061 13.7 % $ 3,305 ≥4.5% $ 4,774 ≥6.5% December 31, 2015 (1) Total capital (to risk-weighted assets) Discover Financial Services $ 12,497 16.5 % $ 6,052 ≥8.0% $ 7,565 ≥10.0% Discover Bank $ 11,905 15.9 % $ 5,991 ≥8.0% $ 7,488 ≥10.0% Tier 1 capital (to risk-weighted assets) Discover Financial Services $ 11,126 14.7 % $ 4,539 ≥6.0% $ 6,052 ≥8.0% Discover Bank $ 9,941 13.3 % $ 4,493 ≥6.0% $ 5,991 ≥8.0% Tier 1 capital (to average assets) Discover Financial Services $ 11,126 12.9 % $ 3,446 ≥4.0% $ 4,307 ≥5.0% Discover Bank $ 9,941 11.7 % $ 3,410 ≥4.0% $ 4,263 ≥5.0% CET1 capital (to risk-weighted assets) (Basel III transition) Discover Financial Services $ 10,566 14.0 % $ 3,404 ≥4.5% $ 4,917 ≥6.5% Discover Bank $ 9,941 13.3 % $ 3,370 ≥4.5% $ 4,867 ≥6.5% (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Commitments, Contingencies an35

Commitments, Contingencies and Guarantees (Tables)	3 Months Ended
	Mar. 31, 2016
Guarantor Obligations [Line Items]
Schedule of Lease Commitments	The Company leases various office space and equipment under capital and non-cancelable operating leases, which expire at various dates through 2028. Future minimum payments on capital leases were not material at March 31, 2016. The following table shows future minimum payments on non-cancelable operating leases with original terms in excess of one year (dollars in millions): March 31, 2016 2016 $ 11 2017 12 2018 11 2019 9 2020 7 Thereafter 34 Total minimum lease payments $ 84
Schedule of Settlement Withholdings and Escrow Deposits	The table below provides information regarding escrow deposits and settlement withholdings, which are recorded in interest-bearing deposit accounts and accrued expenses and other liabilities on the Company’s condensed consolidated statements of financial condition, respectively (dollars in millions): March 31, December 31, Settlement withholdings and escrow deposits $ 6 $ 7
Counterparty Settlement Guarantees [Member]
Guarantor Obligations [Line Items]
Schedule of Maximum Potential Counterparty Exposures Related to Settlement Guarantees and Merchant Chargeback Guarantee	While the Company has some contractual remedies to offset these counterparty settlement exposures (such as letters of credit or pledged deposits), in the event that all licensees and/or issuers were to become unable to settle their transactions, the Company estimates its maximum potential counterparty exposures to these settlement guarantees, based on historical transaction volume, would be as follows (dollars in millions): March 31, Diners Club: Merchant guarantee $ 142 PULSE: ATM guarantee $ 1
Merchant Chargeback Guarantees [Member]
Guarantor Obligations [Line Items]
Schedule of Maximum Potential Counterparty Exposures Related to Settlement Guarantees and Merchant Chargeback Guarantee	The table below summarizes certain information regarding merchant chargeback guarantees (in millions): For the Three Months Ended March 31, 2016 2015 Aggregate sales transaction volume (1) $ 31,281 $ 29,498 (1) Represents period transactions processed on the Discover Network for which a potential liability exists that, in aggregate, can differ from credit card sales volume.

Fair Value Measurements and D36

Fair Value Measurements and Disclosures (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are as follows (dollars in millions): Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance at March 31, 2016 Assets U.S. Treasury securities $ 1,180 $ — $ — $ 1,180 U.S. government agency securities 492 — — 492 Residential mortgage-backed securities - Agency — 1,152 — 1,152 Available-for-sale investment securities $ 1,672 $ 1,152 $ — $ 2,824 Derivative financial instruments $ — $ 58 $ — $ 58 Liabilities Derivative financial instruments $ — $ 78 $ — $ 78 Balance at December 31, 2015 Assets U.S. Treasury securities $ 1,272 $ — $ — $ 1,272 U.S. government agency securities 494 — — 494 Residential mortgage-backed securities - Agency — 1,197 — 1,197 Available-for-sale investment securities $ 1,766 $ 1,197 $ — $ 2,963 Derivative financial instruments $ — $ 22 $ — $ 22 Liabilities Derivative financial instruments $ — $ 38 $ — $ 38
Schedule of Financial Instruments Measured at Other Than Fair Value	The following tables disclose the estimated fair value of the Company's financial assets and financial liabilities that are not required to be carried at fair value (dollars in millions): Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Carrying Value Balance at March 31, 2016 Assets U.S Treasury securities $ 1 $ — $ — $ 1 $ 1 States and political subdivisions of states — 5 — 5 5 Residential mortgage-backed securities - Agency — 129 — 129 126 Held-to-maturity investment securities $ 1 $ 134 $ — $ 135 $ 132 Cash and cash equivalents $ 12,135 $ — $ — $ 12,135 $ 12,135 Restricted cash $ 1,010 $ — $ — $ 1,010 $ 1,010 Net loan receivables $ — $ — $ 69,473 $ 69,473 $ 68,399 Accrued interest receivables $ — $ 666 $ — $ 666 $ 666 Liabilities Deposits $ — $ 48,775 $ — $ 48,775 $ 48,465 Long-term borrowings - owed to securitization investors $ — $ 15,849 $ 1,131 $ 16,980 $ 16,779 Other long-term borrowings $ — $ 8,444 $ — $ 8,444 $ 7,973 Accrued interest payables $ — $ 172 $ — $ 172 $ 172 Balance at December 31, 2015 Assets U.S Treasury securities $ 1 $ — $ — $ 1 $ 1 States and political subdivisions of states — 7 — 7 7 Residential mortgage-backed securities - Agency — 114 — 114 113 Held-to-maturity investment securities $ 1 $ 121 $ — $ 122 $ 121 Cash and cash equivalents $ 9,572 $ — $ — $ 9,572 $ 9,572 Restricted cash $ 99 $ — $ — $ 99 $ 99 Net loan receivables $ — $ — $ 71,455 $ 71,455 $ 70,516 Accrued interest receivables $ — $ 660 $ — $ 660 $ 660 Liabilities Deposits (1) $ — $ 47,714 $ — $ 47,714 $ 47,531 Long-term borrowings - owed to securitization investors (1) $ — $ 15,634 $ 1,220 $ 16,854 $ 16,735 Other long-term borrowings (1) $ — $ 8,355 $ — $ 8,355 $ 7,915 Accrued interest payables $ — $ 158 $ — $ 158 $ 158 (1) Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Derivatives and Hedging Activ37

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Value and Outstanding Notional Amounts of Derivative Instruments and Related Collateral Balances	The following table summarizes the fair value (including accrued interest) and outstanding notional amounts of derivative instruments and related collateral balances (dollars in millions): March 31, 2016 December 31, 2015 Notional Amount Number of Outstanding Derivative Contracts Derivative Assets Derivative Liabilities Notional Amount Derivative Assets Derivative Liabilities Derivatives designated as hedges Interest rate swaps—cash flow hedge $ 4,100 8 $ — $ 78 $ 4,100 $ — $ 35 Interest rate swaps—fair value hedge $ 4,854 105 58 — $ 4,110 22 3 Derivatives not designated as hedges Foreign exchange forward contracts (1) $ 32 6 — — $ 32 — — Interest rate swap (2) $ 198 1 — — $ 217 — — Total gross derivative assets/liabilities (3) 58 78 22 38 Less: Collateral held/posted (4) (21 ) (63 ) (8 ) (33 ) Total net derivative assets/liabilities $ 37 $ 15 $ 14 $ 5 (1) The foreign exchange forward contracts have notional amounts of EUR 19 million , GBP 7 million and SGD 1 million as of March 31, 2016 , and notional amounts of EUR 19 million , GBP 7 million and SGD 1 million as of December 31, 2015 . (2) Interest rate swaps not designated as hedges do not have associated master netting arrangements. (3) In addition to the derivatives disclosed in the table, the Company enters into forward contracts to purchase when-issued mortgage-backed securities as part of its community reinvestment initiatives. At March 31, 2016 , the Company had one outstanding contract with a notional amount of $36 million and immaterial fair value. At December 31, 2015 , the Company had one outstanding contract with a notional amount of $52 million and immaterial fair value. (4) Collateral amounts, which consist of both cash and investment securities, are limited to the related derivative asset/liability balance and do not include excess collateral received/pledged.
Schedule of Impact of the Derivative Instruments on Income and Other Comprehensive Income	The following tables summarize the impact of the derivative instruments on income and OCI and indicates where within the condensed consolidated financial statements such impact is reported (dollars in millions): Amount of Loss Recognized in OCI For the Three Months Ended March 31, Location 2016 2015 Derivatives designated as hedges Interest rate swaps - cash flow/net investment hedges Total loss recognized in OCI after amounts reclassified into earnings, pre-tax OCI $ (43 ) $ (35 ) Total loss recognized in OCI $ (43 ) $ (35 ) Amount of (Loss) Gain Recognized in Income For the Three Months Ended March 31, Location 2016 2015 Derivatives designated as hedges Interest rate swaps - cash flow hedges Amount reclassified from OCI into income Interest Expense $ (9 ) $ (12 ) Total amount reclassified from OCI into income (9 ) (12 ) Interest rate swaps - fair value hedges Adjustments - ineffectiveness 31 5 Adjustments - other 9 8 Gain on interest rate swaps Interest Expense 40 13 Adjustments - ineffectiveness (29 ) (3 ) Adjustments - other (2 ) (1 ) Loss on hedged item Interest Expense (31 ) (4 ) Total loss on derivatives designated as hedges recognized in income $ — $ (3 ) Derivatives not designated as hedges Total (loss) gain on derivatives not designated as hedges recognized in income (1) Other Income $ (1 ) $ 49 (1) Amount as of March 31, 2015 includes $2 million gain on forward delivery contracts and $44 million gain on interest rate lock commitments related to the mortgage loan business that was closed during 2015. See Note 2: Business Dispositions.

Segment Disclosures (Tables)

Segment Disclosures (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Schedule of Segment Disclosures	The following table presents segment data (dollars in millions): Direct Banking Payment Services Total For the Three Months Ended March 31, 2016 Interest income Credit card loans $ 1,733 $ — $ 1,733 Private student loans 107 — 107 PCI student loans 49 — 49 Personal loans 167 — 167 Other 28 — 28 Total interest income 2,084 — 2,084 Interest expense 334 — 334 Net interest income 1,750 — 1,750 Provision for loan losses 423 1 424 Other income 406 68 474 Other expense 851 35 886 Income before income tax expense $ 882 $ 32 $ 914 For the Three Months Ended March 31, 2015 Interest income Credit card loans $ 1,606 $ — $ 1,606 Private student loans 90 — 90 PCI student loans 60 — 60 Personal loans 152 — 152 Other 21 — 21 Total interest income 1,929 — 1,929 Interest expense 300 — 300 Net interest income 1,629 — 1,629 Provision for loan losses 388 2 390 Other income 468 74 542 Other expense 828 45 873 Income before income tax expense $ 881 $ 27 $ 908

Background and Basis of Prese39

Background and Basis of Presentation (Narrative) (Details) - Accounting Standards Update 2015-03 [Member] $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Issuance Cost	$ (137)
Long-term Debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Issuance Cost	74
Deposits [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Issuance Cost	$ 63

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Investment Holdings [Line Items]
Other than temporary impairment loss on investments	$ 0	$ 0
Affordable housing project equity method investments	233		$ 238
Contingent liabilities related to affordable housing project equity method investments	56		57
Community Reinvestment Act [Member] | Other Assets [Member]
Investment Holdings [Line Items]
Equity method investments	315		328
Community Reinvestment Act [Member] | Other Liabilities [Member]
Investment Holdings [Line Items]
Contingent liabilities related to equity method investments	$ 56		$ 57

Investments (Schedule of Invest

Investments (Schedule of Investment Securities) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Investment securities		$ 2,956	$ 3,084
U.S. Treasury Securities [Member]
Investment Holdings [Line Items]
Investment securities	[1]	1,181	1,273
Derivative collateral		20	7
U.S. Government Agency Securities [Member]
Investment Holdings [Line Items]
Investment securities		492	494
States and Political Subdivisions of States [Member]
Investment Holdings [Line Items]
Investment securities		5	7
Residential Mortgage-Backed Securities - Agency [Member]
Investment Holdings [Line Items]
Investment securities	[2]	$ 1,278	$ 1,310
[1]	Includes $20 million and $7 million of U.S. Treasury securities pledged as swap collateral in lieu of cash as of March 31, 2016 and December 31, 2015, respectively.
[2]	Consists of residential mortgage-backed securities issued by Fannie Mae, Freddie Mac and Ginnie Mae.

Investments (Schedule of Amorti

Investments (Schedule of Amortized Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Available-for-sale investment securities, amortized cost	[1]	$ 2,802	$ 2,964
Available-for-sale investment securities, gross unrealized gains	[1]	22	9
Available-for-sale investment securities, gross unrealized losses	[1]	0	(10)
Available-for-sale investment securities, fair value	[1]	2,824	2,963
Held-to-maturity investment securities, amortized cost	[2]	132	121
Held-to-maturity investment securities, gross unrealized gains	[2]	3	1
Held-to-maturity investment securities, gross unrealized losses	[2]	0	0
Held-to-maturity investment securities, fair value	[2]	135	122
U.S. Treasury Securities [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, amortized cost	[1]	1,177	1,277
Available-for-sale investment securities, gross unrealized gains	[1]	3	1
Available-for-sale investment securities, gross unrealized losses	[1]	0	(6)
Available-for-sale investment securities, fair value	[1]	1,180	1,272
Held-to-maturity investment securities, amortized cost	[2],[3]	1	1
Held-to-maturity investment securities, gross unrealized gains	[2],[3]	0	0
Held-to-maturity investment securities, gross unrealized losses	[2],[3]	0	0
Held-to-maturity investment securities, fair value	[2],[3]	1	1
U.S. Government Agency Securities [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, amortized cost	[1]	491	492
Available-for-sale investment securities, gross unrealized gains	[1]	1	2
Available-for-sale investment securities, gross unrealized losses	[1]	0	0
Available-for-sale investment securities, fair value	[1]	492	494
Residential Mortgage-Backed Securities - Agency [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, amortized cost	[1]	1,134	1,195
Available-for-sale investment securities, gross unrealized gains	[1]	18	6
Available-for-sale investment securities, gross unrealized losses	[1]	0	(4)
Available-for-sale investment securities, fair value	[1]	1,152	1,197
Held-to-maturity investment securities, amortized cost	[2],[4]	126	113
Held-to-maturity investment securities, gross unrealized gains	[2],[4]	3	1
Held-to-maturity investment securities, gross unrealized losses	[2],[4]	0	0
Held-to-maturity investment securities, fair value	[2],[4]	129	114
States and Political Subdivisions of States [Member]
Investment Holdings [Line Items]
Held-to-maturity investment securities, amortized cost	[2]	5	7
Held-to-maturity investment securities, gross unrealized gains	[2]	0	0
Held-to-maturity investment securities, gross unrealized losses	[2]	0	0
Held-to-maturity investment securities, fair value	[2]	$ 5	$ 7
[1]	Available-for-sale investment securities are reported at fair value.
[2]	Held-to-maturity investment securities are reported at amortized cost.
[3]	Amount represents securities pledged as collateral to a government-related merchant for which transaction settlement occurs beyond the normal 24-hour period.
[4]	Amounts represent residential mortgage-backed securities that were classified as held-to-maturity as they were entered into as a part of the Company's community reinvestment initiatives.

Investments (Schedule of Fair V

Investments (Schedule of Fair Value of Securities in a Continuous Unrealized Loss Position for Less Than 12 Months and More Than 12 Months) (Details) $ in Millions	Dec. 31, 2015USD ($)securities
U.S. Treasury Securities [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, number of securities in a loss position (in securities) | securities	1
Available-for-sale investment securities, continuous unrealized loss position, less than 12 months, fair value	$ 670
Available-for-sale investment securities, continuous unrealized loss position, less than 12 months, unrealized losses	(6)
Available-for-sale investment securities, continuous unrealized loss position, more than 12 months, fair value	0
Available-for-sale investment securities, continuous unrealized loss position, more than 12 months, unrealized losses	$ 0
Residential Mortgage-Backed Securities - Agency [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, number of securities in a loss position (in securities) | securities	15
Available-for-sale investment securities, continuous unrealized loss position, less than 12 months, fair value	$ 486
Available-for-sale investment securities, continuous unrealized loss position, less than 12 months, unrealized losses	(4)
Available-for-sale investment securities, continuous unrealized loss position, more than 12 months, fair value	0
Available-for-sale investment securities, continuous unrealized loss position, more than 12 months, unrealized losses	$ 0

Investments (Schedule of Procee

Investments (Schedule of Proceeds, Recognized Gains and Losses and Net Unrealized Gains and Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Proceeds from the sales of available-for-sale investment securities	$ 0	$ 899
Gain on sales of available-for-sale investment securities	0	8
Net unrealized gain recorded in other comprehensive income, before-tax	23	0
Net unrealized gain recorded in other comprehensive income, after-tax	$ 14	$ 0

Investments (Schedule of Maturi

Investments (Schedule of Maturities of Available-for-Sale Debt Securities and Held-to-Maturity Debt Securities) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Available-for-sale investment securities, debt maturities, one year or less, amortized cost		$ 991
Available-for-sale investment securities, debt maturities, after one year through five years, amortized cost		677
Available-for-sale investment securities, debt maturities, after five years through ten years, amortized cost		359
Available-for-sale investment securities, debt maturities, after ten years, amortized cost		775
Available-for-sale investment securities, amortized cost	[1]	2,802	$ 2,964
Held-to-maturity investment securities, debt maturities, one year or less, amortized cost		1
Held-to-maturity investment securities, debt maturities, after one year through five years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after ten years, amortized cost		131
Held-to-maturity investment securities, amortized cost	[2]	132	121
Available-for-sale investment securities, debt maturities, one year or less, fair value		993
Available-for-sale investment securities, debt maturities, after one year through five years, fair value		679
Available-for-sale investment securities, debt maturities, after five years through ten years, fair value		363
Available-for-sale investment securities, debt maturities, after ten years, fair value		789
Available-for-sale investment securities, fair value	[1]	2,824	2,963
Held-to-maturity investment securities, debt maturities, one year or less, fair value		1
Held-to-maturity investment securities, debt maturities, after one year through five years, fair value		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, fair value		0
Held-to-maturity investment securities, debt maturities, after ten years, fair value		134
Held-to-maturity investment securities, fair value	[2]	135	122
U.S. Treasury Securities [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, debt maturities, one year or less, amortized cost		500
Available-for-sale investment securities, debt maturities, after one year through five years, amortized cost		677
Available-for-sale investment securities, debt maturities, after five years through ten years, amortized cost		0
Available-for-sale investment securities, debt maturities, after ten years, amortized cost		0
Available-for-sale investment securities, amortized cost	[1]	1,177	1,277
Held-to-maturity investment securities, debt maturities, one year or less, amortized cost		1
Held-to-maturity investment securities, debt maturities, after one year through five years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after ten years, amortized cost		0
Held-to-maturity investment securities, amortized cost	[2],[3]	1	1
Available-for-sale investment securities, debt maturities, one year or less, fair value		501
Available-for-sale investment securities, debt maturities, after one year through five years, fair value		679
Available-for-sale investment securities, debt maturities, after five years through ten years, fair value		0
Available-for-sale investment securities, debt maturities, after ten years, fair value		0
Available-for-sale investment securities, fair value	[1]	1,180	1,272
Held-to-maturity investment securities, debt maturities, one year or less, fair value		1
Held-to-maturity investment securities, debt maturities, after one year through five years, fair value		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, fair value		0
Held-to-maturity investment securities, debt maturities, after ten years, fair value		0
Held-to-maturity investment securities, fair value	[2],[3]	1	1
U.S. Government Agency Securities [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, debt maturities, one year or less, amortized cost		491
Available-for-sale investment securities, debt maturities, after one year through five years, amortized cost		0
Available-for-sale investment securities, debt maturities, after five years through ten years, amortized cost		0
Available-for-sale investment securities, debt maturities, after ten years, amortized cost		0
Available-for-sale investment securities, amortized cost	[1]	491	492
Available-for-sale investment securities, debt maturities, one year or less, fair value		492
Available-for-sale investment securities, debt maturities, after one year through five years, fair value		0
Available-for-sale investment securities, debt maturities, after five years through ten years, fair value		0
Available-for-sale investment securities, debt maturities, after ten years, fair value		0
Available-for-sale investment securities, fair value	[1]	492	494
Residential Mortgage-Backed Securities - Agency [Member]
Investment Holdings [Line Items]
Available-for-sale investment securities, debt maturities, one year or less, amortized cost		0
Available-for-sale investment securities, debt maturities, after one year through five years, amortized cost		0
Available-for-sale investment securities, debt maturities, after five years through ten years, amortized cost		359
Available-for-sale investment securities, debt maturities, after ten years, amortized cost		775
Available-for-sale investment securities, amortized cost	[1]	1,134	1,195
Held-to-maturity investment securities, debt maturities, one year or less, amortized cost		0
Held-to-maturity investment securities, debt maturities, after one year through five years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after ten years, amortized cost		126
Held-to-maturity investment securities, amortized cost	[2],[4]	126	113
Available-for-sale investment securities, debt maturities, one year or less, fair value		0
Available-for-sale investment securities, debt maturities, after one year through five years, fair value		0
Available-for-sale investment securities, debt maturities, after five years through ten years, fair value		363
Available-for-sale investment securities, debt maturities, after ten years, fair value		789
Available-for-sale investment securities, fair value	[1]	1,152	1,197
Held-to-maturity investment securities, debt maturities, one year or less, fair value		0
Held-to-maturity investment securities, debt maturities, after one year through five years, fair value		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, fair value		0
Held-to-maturity investment securities, debt maturities, after ten years, fair value		129
Held-to-maturity investment securities, fair value	[2],[4]	129	114
States and Political Subdivisions of States [Member]
Investment Holdings [Line Items]
Held-to-maturity investment securities, debt maturities, one year or less, amortized cost		0
Held-to-maturity investment securities, debt maturities, after one year through five years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, amortized cost		0
Held-to-maturity investment securities, debt maturities, after ten years, amortized cost		5
Held-to-maturity investment securities, amortized cost	[2]	5	7
Held-to-maturity investment securities, debt maturities, one year or less, fair value		0
Held-to-maturity investment securities, debt maturities, after one year through five years, fair value		0
Held-to-maturity investment securities, debt maturities, after five years through ten years, fair value		0
Held-to-maturity investment securities, debt maturities, after ten years, fair value		5
Held-to-maturity investment securities, fair value	[2]	$ 5	$ 7
[1]	Available-for-sale investment securities are reported at fair value.
[2]	Held-to-maturity investment securities are reported at amortized cost.
[3]	Amount represents securities pledged as collateral to a government-related merchant for which transaction settlement occurs beyond the normal 24-hour period.
[4]	Amounts represent residential mortgage-backed securities that were classified as held-to-maturity as they were entered into as a part of the Company's community reinvestment initiatives.

Loan Receivables (Narrative) (D

Loan Receivables (Narrative) (Details) $ in Millions		3 Months Ended			12 Months Ended
		Mar. 31, 2016USD ($)segment		Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)		Dec. 31, 2014USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan portfolio segments (in segments) | segment		3
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		$ 476			$ 460
Private student loan forbearance lifetime cap (in months)		12 months
Private student loans including PCI in forbearance		$ 31			$ 31
Private student loans in forbearance as a percentage of student loans in repayment and forbearance (in percent)		0.50%			0.50%
Percentage of defaulted loans that were charged off at the end of the month in which they defaulted (in percent)		37.00%		43.00%
Provision for loan losses on PCI loans		$ 424		$ 390
Allowance for loan losses on PCI loans		$ 1,921		$ 1,776	$ 1,869		$ 1,746
Net charge-off rate on PCI student loans (in percent)		2.11%		2.14%
Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum period of payment reduction for the temporary reduced payment program (in months)		12 months
Maximum forbearance period for student loan borrowers (in months)		12 months
Period triggering TDR accounting for the temporary reduced payment program (in months)		12 months
Provision for loan losses on PCI loans	[1]	$ 17		$ 20
Allowance for loan losses on PCI loans	[1]	$ 148	[2]	142	143	[2]	135
Personal Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum period of payment reduction for the temporary reduced payment program (in months)		12 months
Maximum repayment term for temporary modification programs (in years)		9 years
Maximum repayment term for permanent modification programs (in years)		9 years
Total Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		$ 49			38
Total Other Loans [Member] | Personal Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	[3]	13			13
Provision for loan losses on PCI loans		44		31
Allowance for loan losses on PCI loans		165		123	155		120
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	[4]	36			25
Credit Card Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	[5]	$ 427			422
Maximum period of payment reduction for the temporary reduced payment program (in months)		12 months
Permanent workout program maturity (in months)		60 months
Interest and fees forgiven due to credit card loan modification program		$ 9		11
Provision for loan losses on PCI loans		362		337
Allowance for loan losses on PCI loans		1,590		1,492	1,554		$ 1,474
PCI Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit-impaired loans outstanding balance		3,200			3,300
Purchased credit-impaired loans	[6]	2,965			3,116
Provision for loan losses on PCI loans		0		$ 0
Allowance for loan losses on PCI loans		$ 36			$ 36
Threshold Period Past Due for Write-off of Financing Receivable		120 days
Net charge-off rate on PCI student loans (in percent)		0.43%		0.50%
PCI Student Loans [Member] | 30 or More Days Delinquent [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Delinquency rate on PCI student loans (in percent)		2.18%			2.53%
PCI Student Loans [Member] | 90 or More Days Delinquent [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Delinquency rate on PCI student loans (in percent)		0.73%			0.88%
Entity Loan Modification Program [Member] | Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		$ 3			$ 3
Internal And External Loan Modification Programs [Member] | Total Other Loans [Member] | Personal Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		4			4
Internal And External Loan Modification Programs [Member] | Credit Card Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing		$ 44			$ 42
[1]	Includes both PCI and non-PCI private student loans.
[2]	Includes both PCI and non-PCI private student loans.
[3]	Personal loans that are 90 or more days delinquent and accruing interest include $4 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015.
[4]	Private student loans that are 90 or more days delinquent and accruing interest include $3 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015.
[5]	Credit card loans that are 90 or more days delinquent and accruing interest include $44 million and $42 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015, respectively.
[6]	Amounts include $1.6 billion and $1.7 billion of loans pledged as collateral against the notes issued from the Student Loan Corporation ("SLC") securitization trusts at March 31, 2016 and December 31, 2015, respectively. See Note 5: Credit Card and Student Loan Securitization Activities.

Loan Receivables (Schedule of L

Loan Receivables (Schedule of Loan Receivables) (Details) - USD ($) $ in Millions		Mar. 31, 2016		Dec. 31, 2015		Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan receivables		$ 70,320		$ 72,385
Allowance for loan losses		(1,921)		(1,869)		$ (1,776)	$ (1,746)
Net loan receivables		68,399		70,516
Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loan receivables		28,761		30,551
Allowance for loan losses		(811)		(811)
Credit Card Securitization Trusts [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit card loans	[1]	27,165		28,873
Allowance for loan losses	[1]	(783)		(783)
Sellers' interest		6,241		7,231
Student Loan Securitization Trusts [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit-impaired loans	[2]	1,596		1,678
Allowance for loan losses	[2]	(28)		(28)
Credit Card Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit card loans	[3]	55,620		57,896
Allowance for loan losses		(1,590)		(1,554)		(1,492)	(1,474)
Credit Card Loans [Member] | Credit Card Securitization Trusts [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investors' interest		20,900		21,600
Total Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other loans		11,735		11,373
Total Other Loans [Member] | Personal Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other loans		5,534		5,490
Allowance for loan losses		(165)		(155)		(123)	(120)
Total Other Loans [Member] | Private Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other loans		5,949		5,647
Total Other Loans [Member] | Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total other loans		252		236
Allowance for loan losses		(18)	[4]	(17)	[4]	$ (19)	$ (17)
Purchase Credit-Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit-impaired loans	[5]	2,965		3,116
Allowance for loan losses		(36)		(36)
Purchase Credit-Impaired Loans [Member] | Student Loan Securitization Trusts [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged as collateral		$ 1,600		$ 1,700
[1]	The Company maintains its allowance for loan losses at an amount sufficient to absorb probable losses inherent in all loan receivables, which includes all loan receivables in the trusts. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company’s balance sheet in accordance with GAAP.
[2]	The Company maintains its allowance for loan losses on PCI loans sufficient to absorb probable decreases in cash flows that were previously expected. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company's balance sheet in accordance with GAAP.
[3]	Amounts include $20.9 billion and $21.6 billion underlying investors’ interest in trust debt at March 31, 2016 and December 31, 2015 and $6.2 billion and $7.2 billion in seller's interest at March 31, 2016 and December 31, 2015, respectively. See Note 5: Credit Card and Student Loan Securitization Activities for further information.
[4]	Certain other loans, including non-performing Diners Club licensee loans, are individually evaluated for impairment.
[5]	Amounts include $1.6 billion and $1.7 billion of loans pledged as collateral against the notes issued from the Student Loan Corporation ("SLC") securitization trusts at March 31, 2016 and December 31, 2015, respectively. See Note 5: Credit Card and Student Loan Securitization Activities.

Loan Receivables (Schedule of D

Loan Receivables (Schedule of Delinquent and Non-Accruing Loans) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		$ 1,105		$ 1,153
Loan receivables, 90 or more days delinquent and accruing		476		460
Loan receivables, total non-accruing		216		224
30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		574		623
90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		531		530
Credit Card Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		934		995
Loan receivables, 90 or more days delinquent and accruing	[1]	427		422
Loan receivables, total non-accruing	[2]	190		198
Estimated gross interest income that would have been recorded based on original terms		8	$ 7
Credit Card Loans [Member] | Internal And External Loan Modification Programs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, 90 or more days delinquent and accruing		44		42
Credit Card Loans [Member] | 30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		454		505
Credit Card Loans [Member] | 90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		480		490
Total Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		171		158
Loan receivables, 90 or more days delinquent and accruing		49		38
Loan receivables, total non-accruing		26		26
Total Other Loans [Member] | 30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		120		118
Total Other Loans [Member] | 90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		51		40
Total Other Loans [Member] | Personal Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		54		49
Loan receivables, 90 or more days delinquent and accruing	[3]	13		13
Loan receivables, total non-accruing		6		6
Total Other Loans [Member] | Personal Loans [Member] | Internal And External Loan Modification Programs [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, 90 or more days delinquent and accruing		4		4
Total Other Loans [Member] | Personal Loans [Member] | 30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		40		34
Total Other Loans [Member] | Personal Loans [Member] | 90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		14		15
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		114		108
Loan receivables, 90 or more days delinquent and accruing	[4]	36		25
Loan receivables, total non-accruing		0		0
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | Entity Loan Modification Program [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, 90 or more days delinquent and accruing		3		3
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | 30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		78		84
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | 90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		36		24
Total Other Loans [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		3		1
Loan receivables, 90 or more days delinquent and accruing		0		0
Loan receivables, total non-accruing		20		20
Total Other Loans [Member] | Other Loans [Member] | 30-89 Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		2		0
Total Other Loans [Member] | Other Loans [Member] | 90 or More Days Delinquent [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loan receivables, past due		$ 1		$ 1
[1]	Credit card loans that are 90 or more days delinquent and accruing interest include $44 million and $42 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015, respectively.
[2]	The Company estimates that the gross interest income that would have been recorded in accordance with the original terms of non-accruing credit card loans was $8 million and $7 million for the three months ended March 31, 2016 and 2015, respectively. The Company does not separately track the amount of gross interest income that would have been recorded in accordance with the original terms of loans. This amount was estimated based on customers' current balances and most recent interest rates.
[3]	Personal loans that are 90 or more days delinquent and accruing interest include $4 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015.
[4]	Private student loans that are 90 or more days delinquent and accruing interest include $3 million of loans accounted for as troubled debt restructurings at March 31, 2016 and December 31, 2015.

Loan Receivables (Schedule of N

Loan Receivables (Schedule of Net Charge-offs) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Charge Offs [Line Items]
Net charge-offs	$ 372	$ 360
Net charge-off rate (in percent)	2.11%	2.14%
Excluding PCI Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 372	$ 360
Net charge-off rate (in percent)	2.21%	2.26%
Credit Card Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 326	$ 319
Credit Card Loans [Member] | Excluding PCI Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 326	$ 319
Net charge-off rate (in percent)	2.34%	2.40%
Total Other Loans [Member] | Excluding PCI Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 46	$ 41
Net charge-off rate (in percent)	1.59%	1.58%
Total Other Loans [Member] | Personal Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 34	$ 28
Total Other Loans [Member] | Personal Loans [Member] | Excluding PCI Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 34	$ 28
Net charge-off rate (in percent)	2.45%	2.22%
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | Excluding PCI Loans [Member]
Charge Offs [Line Items]
Net charge-offs	$ 12	$ 13
Net charge-off rate (in percent)	0.85%	1.03%

Loan Receivables (Schedule of C

Loan Receivables (Schedule of Credit Risk Profile by FICO Score) (Details)		Mar. 31, 2016	Dec. 31, 2015
Credit Card Loans [Member] | FICO Score, 660 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables		82.00%	83.00%
Credit Card Loans [Member] | FICO Score, Less Than 660 Or No Score [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables		18.00%	17.00%
Total Other Loans [Member] | Personal Loans [Member] | FICO Score, 660 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables		96.00%	96.00%
Total Other Loans [Member] | Personal Loans [Member] | FICO Score, Less Than 660 Or No Score [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables		4.00%	4.00%
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | FICO Score, 660 and Above [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables	[1]	96.00%	96.00%
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member] | FICO Score, Less Than 660 Or No Score [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
FICO scores as a percentage of class of loan receivables	[1]	4.00%	4.00%
[1]	PCI loans are discussed under the heading "— Purchased Credit-Impaired Loans."

Loan Receivables (Schedule of51

Loan Receivables (Schedule of Changes in the Allowance for Loan Losses) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period		$ 1,869		$ 1,746
Provision for loan losses		424		390
Charge-offs		(493)		(474)
Recoveries		121		114
Net charge-offs		(372)		(360)
Balance at end of period		1,921		1,776
Student Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	[2]	143	[1]	135
Provision for loan losses	[2]	17		20
Charge-offs	[2]	(15)		(15)
Recoveries	[2]	3		2
Net charge-offs	[2]	(12)		(13)
Balance at end of period	[2]	148	[1]	142
Credit Card Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period		1,554		1,474
Provision for loan losses		362		337
Charge-offs		(439)		(428)
Recoveries		113		109
Net charge-offs		(326)		(319)
Balance at end of period		1,590		1,492
Total Other Loans [Member] | Personal Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period		155		120
Provision for loan losses		44		31
Charge-offs		(39)		(31)
Recoveries		5		3
Net charge-offs		(34)		(28)
Balance at end of period		165		123
Total Other Loans [Member] | Other Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period		17	[3]	17
Provision for loan losses		1		2
Charge-offs		0		0
Recoveries		0		0
Net charge-offs		0		0
Balance at end of period		$ 18	[3]	$ 19
[1]	Includes both PCI and non-PCI private student loans.
[2]	Includes both PCI and non-PCI private student loans.
[3]	Certain other loans, including non-performing Diners Club licensee loans, are individually evaluated for impairment.

Loan Receivables (Schedule of52

Loan Receivables (Schedule of Net Charge-offs of Interest and Fee Revenues on Loan Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Loans and Leases Receivable Disclosure [Abstract]
Interest and fees accrued subsequently charged off, net of recoveries (recorded as a reduction of interest income)	$ 69	$ 75
Fees accrued subsequently charged off, net of recoveries (recorded as a reduction to other income)	$ 17	$ 20

Loan Receivables (Schedule of A

Loan Receivables (Schedule of Allowance for Loan Losses and Recorded Investment in its Loan Portfolio by Impairment Methodology) (Details) - USD ($) $ in Millions		Mar. 31, 2016		Dec. 31, 2015		Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, collectively evaluated for impairment in accordance with ASC 450-20		$ 1,676		$ 1,627
Allowance for loan losses, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	209		206
Total allowance for loan losses		1,921		1,869		$ 1,776	$ 1,746
Recorded investment in loans, collectively evaluated for impairment in accordance with ASC 450-20		66,154		68,077
Recorded investment in loans, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	1,201		1,192
Total recorded investment		70,320		72,385
Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loans losses, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		36		36
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		2,965		3,116
Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total allowance for loan losses	[4]	148	[3]	143	[3]	142	135
Total recorded investment	[3]	8,914		8,763
Credit Card Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, collectively evaluated for impairment in accordance with ASC 450-20		1,430		1,394
Allowance for loan losses, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	160		160
Total allowance for loan losses		1,590		1,554		1,492	1,474
Recorded investment in loans, collectively evaluated for impairment in accordance with ASC 450-20		54,600		56,877
Recorded investment in loans, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	1,020		1,019
Total recorded investment		55,620		57,896
Unpaid principal balance of modified loans accounted for as troubled debt restructurings		873		869
Credit Card Loans [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loans losses, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		0		0
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		0		0
Total Other Loans [Member] | Personal Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, collectively evaluated for impairment in accordance with ASC 450-20		149		140
Allowance for loan losses, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	16		15
Total allowance for loan losses		165		155		123	120
Recorded investment in loans, collectively evaluated for impairment in accordance with ASC 450-20		5,464		5,422
Recorded investment in loans, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	70		68
Total recorded investment		5,534		5,490
Unpaid principal balance of modified loans accounted for as troubled debt restructurings		69		67
Total Other Loans [Member] | Personal Loans [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loans losses, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		0		0
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		0		0
Total Other Loans [Member] | Private Student Loans (Excluding PCI) [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, collectively evaluated for impairment in accordance with ASC 450-20		96		92
Allowance for loan losses, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	16		15
Recorded investment in loans, collectively evaluated for impairment in accordance with ASC 450-20		5,896		5,599
Recorded investment in loans, evaluated for impairment in accordance with ASC 310-10-35	[1],[2]	53		48
Unpaid principal balance of modified loans accounted for as troubled debt restructurings		52		47
Total Other Loans [Member] | Other Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses, collectively evaluated for impairment in accordance with ASC 450-20	[5]	1		1
Allowance for loan losses, evaluated for impairment in accordance with ASC 310-10-35	[1],[2],[5]	17		16
Total allowance for loan losses		18	[5]	17	[5]	$ 19	$ 17
Recorded investment in loans, collectively evaluated for impairment in accordance with ASC 450-20	[5]	194		179
Recorded investment in loans, evaluated for impairment in accordance with ASC 310-10-35	[1],[2],[5]	58		57
Total recorded investment	[5]	252		236
Total Other Loans [Member] | Other Loans [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loans losses, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30	[5]	0		0
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30	[5]	0		0
PCI Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total allowance for loan losses		36		36
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30	[6]	2,965		3,116
PCI Student Loans [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loans losses, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		36		36
Recorded investment in loans, acquired with deteriorated credit quality, evaluated in accordance with ASC 310-30		$ 2,965		$ 3,116
[1]	Loan receivables evaluated for impairment in accordance with Accounting Standards Codification ("ASC") 310-10-35 include credit card loans, personal loans and student loans collectively evaluated for impairment in accordance with ASC Subtopic 310-40, Receivables, which consists of modified loans accounted for as troubled debt restructurings. Other loans are individually evaluated for impairment and generally do not represent troubled debt restructurings.
[2]	The unpaid principal balance of credit card loans was $873 million and $869 million at March 31, 2016 and December 31, 2015, respectively. The unpaid principal balance of personal loans was $69 million and $67 million at March 31, 2016 and December 31, 2015, respectively. The unpaid principal balance of student loans was $52 million and $47 million at March 31, 2016 and December 31, 2015, respectively. All loans accounted for as troubled debt restructurings have a related allowance for loan losses.
[3]	Includes both PCI and non-PCI private student loans.
[4]	Includes both PCI and non-PCI private student loans.
[5]	Certain other loans, including non-performing Diners Club licensee loans, are individually evaluated for impairment.
[6]	Amounts include $1.6 billion and $1.7 billion of loans pledged as collateral against the notes issued from the Student Loan Corporation ("SLC") securitization trusts at March 31, 2016 and December 31, 2015, respectively. See Note 5: Credit Card and Student Loan Securitization Activities.

Loan Receivables (Schedule of T

Loan Receivables (Schedule of Troubled Debt Restructurings) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Credit Card Loans [Member] | Modified Credit Card Loans [Member]
Financing Receivable, Modifications [Line Items]
Average recorded investment in loans	[1]	$ 274	$ 255
Interest income recognized during period loans were impaired	[1],[2]	12	11
Gross interest income that would have been recorded with original terms	[1],[3]	1	1
Credit Card Loans [Member] | Internal Programs [Member]
Financing Receivable, Modifications [Line Items]
Average recorded investment in loans		464	452
Interest income recognized during period loans were impaired	[2]	3	3
Gross interest income that would have been recorded with original terms	[3]	16	15
Credit Card Loans [Member] | External Programs [Member]
Financing Receivable, Modifications [Line Items]
Average recorded investment in loans		283	323
Interest income recognized during period loans were impaired	[2]	5	6
Gross interest income that would have been recorded with original terms	[3]	3	3
Total Other Loans [Member] | Personal Loans [Member] | Internal And External Loan Modification Programs [Member]
Financing Receivable, Modifications [Line Items]
Average recorded investment in loans		69	57
Interest income recognized during period loans were impaired	[2]	2	2
Gross interest income that would have been recorded with original terms	[3]	1	1
Total Other Loans [Member] | Private Student Loans [Member] | Entity Loan Modification Program [Member]
Financing Receivable, Modifications [Line Items]
Average recorded investment in loans		50	40
Interest income recognized during period loans were impaired	[2]	$ 1	$ 1
[1]	This balance is considered impaired, but is excluded from the internal and external program amounts reflected in this table. Represents credit card loans that were modified in troubled debt restructurings, but are no longer enrolled in troubled debt restructuring program due to noncompliance with the terms of the modification or successful completion of a program.
[2]	The Company does not separately track interest income on loans in modification programs. Amounts shown are estimated by applying an average interest rate to the average loans in the various modification programs.
[3]	The Company does not separately track the amount of gross interest income that would have been recorded if the loans in modification programs had not been restructured and interest had instead been recorded in accordance with the original terms. Amounts shown are estimated by applying the difference between the average interest rate earned on non-impaired loans and the average interest rate earned on loans in the modification programs to the average loans in the modification programs.

Loan Receivables (Schedule of55

Loan Receivables (Schedule of Loans That Entered a Modification Program During the Period) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)accounts	Mar. 31, 2015USD ($)accounts
Credit Card Loans [Member] | Internal Programs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts that entered a loan modification program during the period, number of accounts (in accounts) | accounts	14,967	13,243
Accounts that entered a loan modification program during the period, balances | $	$ 96	$ 86
Credit Card Loans [Member] | External Programs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts that entered a loan modification program during the period, number of accounts (in accounts) | accounts	7,317	7,617
Accounts that entered a loan modification program during the period, balances | $	$ 39	$ 39
Total Other Loans [Member] | Personal Loans [Member] | Internal And External Loan Modification Programs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts that entered a loan modification program during the period, number of accounts (in accounts) | accounts	1,061	986
Accounts that entered a loan modification program during the period, balances | $	$ 12	$ 12
Total Other Loans [Member] | Private Student Loans [Member] | Entity Loan Modification Program [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts that entered a loan modification program during the period, number of accounts (in accounts) | accounts	452	469
Accounts that entered a loan modification program during the period, balances | $	$ 8	$ 7

Loan Receivables (Schedule of56

Loan Receivables (Schedule of Troubled Debt Restructurings That Subsequently Defaulted) (Details) $ in Millions		3 Months Ended
		Mar. 31, 2016USD ($)missed_paymentsaccounts	Mar. 31, 2015USD ($)accounts
Financing Receivable, Modifications [Line Items]
Amount of missed payments after which a customer defaults from a modification program (in payments) | missed_payments		2
Credit Card Loans [Member] | Internal Programs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings that subsequently defaulted, number of accounts (in accounts) | accounts	[1],[2]	3,001	3,176
Troubled debt restructurings that subsequently defaulted, aggregated outstanding balances upon default | $	[1],[2]	$ 18	$ 20
Credit Card Loans [Member] | External Programs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings that subsequently defaulted, number of accounts (in accounts) | accounts	[1],[2]	1,699	1,643
Troubled debt restructurings that subsequently defaulted, aggregated outstanding balances upon default | $	[1],[2]	$ 7	$ 7
Total Other Loans [Member] | Personal Loans [Member] | Internal And External Loan Modification Programs [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings that subsequently defaulted, number of accounts (in accounts) | accounts	[1]	158	151
Troubled debt restructurings that subsequently defaulted, aggregated outstanding balances upon default | $	[1]	$ 2	$ 2
Total Other Loans [Member] | Private Student Loans [Member]
Financing Receivable, Modifications [Line Items]
Delinquency days to default (in days)		60 days
Total Other Loans [Member] | Private Student Loans [Member] | Entity Loan Modification Program [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings that subsequently defaulted, number of accounts (in accounts) | accounts	[3]	197	305
Troubled debt restructurings that subsequently defaulted, aggregated outstanding balances upon default | $	[3]	$ 3	$ 4
[1]	A customer defaults from a modification program after two consecutive missed payments.
[2]	The outstanding balance upon default is the loan balance at the end of the month prior to default. Terms revert back to the pre-modification terms for customers who default from a temporary program and charging privileges remain revoked in most cases.
[3]	Student loan defaults have been defined as loans that are 60 or more days delinquent.

Loan Receivables (Schedule of57

Loan Receivables (Schedule of Changes in Accretable Yield for the Acquired Loans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, balance at beginning of period	$ 965	$ 1,341
Accretion into interest income	(49)	(59)
Other changes in expected cash flows	0	(101)
Accretable yield, balance at end of period	$ 916	$ 1,181

Credit Card and Student Loan 58

Credit Card and Student Loan Securitization Activities (Narrative) (Details)	3 Months Ended
	Mar. 31, 2016classestrusts
Credit Card Securitization Trusts [Member]
Variable Interest Entity [Line Items]
Excess spread rate minimum	0.00%
Excess of the total investors' interests	7.00%
Student Loan Securitization Trusts [Member]
Variable Interest Entity [Line Items]
Number of trusts issuing securities (in trusts) | trusts	3
Discover Card Execution Note Trust [Member] | Credit Card Securitization Trusts [Member]
Variable Interest Entity [Line Items]
Number of classes of securities in debt structure (in classes) | classes	4
Average excess spread rate calculation period (in months)	3 months

Credit Card and Student Loan 59

Credit Card and Student Loan Securitization Activities (Schedule of Restricted Credit Card Securitized Assets) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015		Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Restricted cash		$ 1,010	$ 99
Allowance for loan losses allocated to securitized loan receivables		(1,921)	(1,869)		$ (1,776)	$ (1,746)
Other		2,465	2,412
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash		1,010	99
Allowance for loan losses allocated to securitized loan receivables		(811)	(811)
Other		6	5
Variable Interest Entity, Primary Beneficiary [Member] | Credit Card Securitization Trusts [Member]
Variable Interest Entity [Line Items]
Restricted cash		921	19
Investors’ interests held by third-party investors		15,725	15,625
Investors’ interests held by wholly-owned subsidiaries of Discover Bank		5,199	6,017
Seller’s interest		6,241	7,231
Loan receivables	[1]	27,165	28,873
Allowance for loan losses allocated to securitized loan receivables	[1]	(783)	(783)
Net loan receivables		26,382	28,090
Other		6	5	[2]
Carrying value of assets of consolidated variable interest entities		$ 27,309	$ 28,114
[1]	The Company maintains its allowance for loan losses at an amount sufficient to absorb probable losses inherent in all loan receivables, which includes all loan receivables in the trusts. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company’s balance sheet in accordance with GAAP.
[2]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Credit Card and Student Loan 60

Credit Card and Student Loan Securitization Activities (Schedule of Investors' Interests and Related Excess Spreads) (Details) - Discover Card Execution Note Trust [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)series
Variable Interest Entity [Line Items]
Investors' interests | $	$ 20,924	[1]
Number of series outstanding (in series) | series	36
Three month rolling average excess spread (in percent)	13.55%
[1]	Investors’ interests include third-party interests and subordinated interests held by wholly-owned subsidiaries of Discover Bank.

Credit Card and Student Loan 61

Credit Card and Student Loan Securitization Activities (Schedule of Restricted Student Loan Securitized Assets) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Restricted cash		$ 1,010	$ 99
Allowance for loan losses allocated to securitized loan receivables		(1,921)	(1,869)	$ (1,776)	$ (1,746)
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Restricted cash		1,010	99
Allowance for loan losses allocated to securitized loan receivables		(811)	(811)
Variable Interest Entity, Primary Beneficiary [Member] | Student Loan Securitization Trusts [Member]
Variable Interest Entity [Line Items]
Restricted cash		89	80
Purchased credit-impaired loans	[1]	1,596	1,678
Allowance for loan losses allocated to securitized loan receivables	[1]	(28)	(28)
Net student loan receivables		1,568	1,650
Carrying value of assets of consolidated variable interest entities		$ 1,657	$ 1,730
[1]	The Company maintains its allowance for loan losses on PCI loans sufficient to absorb probable decreases in cash flows that were previously expected. Therefore, credit risk associated with the transferred receivables is fully reflected on the Company's balance sheet in accordance with GAAP.

Deposits (Narrative) (Details)

Deposits (Narrative) (Details)	3 Months Ended
	Mar. 31, 2016channels
Deposits [Abstract]
Deposits source channels (in number of channels)	2

Deposits (Schedule of Interest

Deposits (Schedule of Interest Bearing Deposit Accounts) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Deposits [Abstract]
Certificates of deposit in amounts less than $100,000		$ 19,728	$ 20,491	[1]
Certificates of deposit in amounts $100,000 or greater	[2]	5,516	5,228
Savings deposits, including money market deposit accounts		22,811	21,375
Total interest-bearing deposits		48,055	47,094	[1]
Certificates of deposit greater than $250,000		$ 1,200	$ 1,100
[1]	(1)Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.
[2]	Includes $1.2 billion and $1.1 billion in certificates of deposit greater than $250,000, the Federal Deposit Insurance Corporation ("FDIC") insurance limit, as of March 31, 2016 and December 31, 2015, respectively.

Deposits (Schedule of $100,000

Deposits (Schedule of $100,000 or More Certificates of Deposit Maturities) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Deposits [Abstract]
Three months or less		$ 530
Over three months through six months		742
Over six months through twelve months		1,536
Over twelve months		2,708
Total	[1]	$ 5,516	$ 5,228
[1]	Includes $1.2 billion and $1.1 billion in certificates of deposit greater than $250,000, the Federal Deposit Insurance Corporation ("FDIC") insurance limit, as of March 31, 2016 and December 31, 2015, respectively.

Deposits (Schedule of Certifica

Deposits (Schedule of Certificates of Deposit Maturities) (Details) $ in Millions	Mar. 31, 2016USD ($)
Deposits [Abstract]
2,016	$ 8,335
2,017	6,792
2,018	3,607
2,019	1,966
2,020	1,938
Thereafter	2,606
Total	$ 25,244

Long-Term Borrowings (Narrative

Long-Term Borrowings (Narrative) (Details) - Discover Card Master Trust I and Discover Card Execution Note Trust [Member] - Secured Debt [Member] $ in Millions	Mar. 31, 2016USD ($)
Debt Instrument [Line Items]
Total commitment of secured credit facilities	$ 6,000
Total used commitment of secured credit facilities	$ 0

Long-Term Borrowings (Schedule

Long-Term Borrowings (Schedule of Long-Term Borrowings and Weighted Average Interest Rates) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Dec. 31, 2015
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		$ 24,752		$ 24,650	[1]
Variable Interest Entity, Primary Beneficiary [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		16,779		16,735	[1]
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		$ 15,709		15,592	[1]
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Fixed-Rate Asset-Backed Securities [Member]
Debt Instrument [Line Items]
Interest rate minimum		1.04%
Interest rate maximum		5.65%
Weighted-average interest rate		2.05%
Long-term borrowings (in dollars)	[2]	$ 9,268		9,152	[1]
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Floating-Rate Asset-Backed Securities [Member]
Debt Instrument [Line Items]
Interest rate minimum		0.62%
Interest rate maximum		0.89%
Weighted-average interest rate		0.79%
Long-term borrowings (in dollars)	[3],[4]	$ 6,441		6,440	[1]
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Floating Rate Asset Backed Securities 1-Month LIBOR Plus Various Basis Points [Member]
Debt Instrument [Line Items]
Interest rate terms		1-month LIBOR + 18 to 45 basis points
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Floating Rate Asset Backed Securities 1-Month LIBOR Plus Various Basis Points [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.18%
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Floating Rate Asset Backed Securities 1-Month LIBOR Plus Various Basis Points [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.45%
Securitized Debt [Member] | Discover Card Master Trust I and Discover Card Execution Note Trust [Member] | Floating Rate Asset Backed Securities 3-Month LIBOR Plus 20 Basis Points [Member]
Debt Instrument [Line Items]
Interest rate terms		3-month LIBOR + 20 basis points
Basis spread on variable rate		0.20%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		$ 1,070		1,143
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating-Rate Asset-Backed Securities [Member]
Debt Instrument [Line Items]
Interest rate minimum		0.79%
Interest rate maximum		4.25%
Weighted-average interest rate		2.21%
Long-term borrowings (in dollars)	[6],[8]	$ 1,070	[5],[7]	1,143
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities 3-Month LIBOR Plus Various Basis Points [Member]
Debt Instrument [Line Items]
Interest rate terms		3-month LIBOR + 17 to 45 basis points
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities 3-Month LIBOR Plus Various Basis Points [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.17%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities 3-Month LIBOR Plus Various Basis Points [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.45%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities Prime Rate Plus 75 to 100 Basis Points [Member]
Debt Instrument [Line Items]
Interest rate terms		Prime rate + 75 to 100 basis points
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities Prime Rate Plus 75 to 100 Basis Points [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		0.75%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities Prime Rate Plus 75 to 100 Basis Points [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Floating Rate Asset Backed Securities 1-Month LIBOR Plus 350 Basis Points [Member]
Debt Instrument [Line Items]
Interest rate terms		1-month LIBOR + 350 basis points
Basis spread on variable rate		3.50%
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Senior Notes Maturing 2031 [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		$ 302
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Senior and Subordinated Notes Maturing 2036 [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		621
Securitized Debt [Member] | SLC Private Student Loan Trust [Member] | Senior Notes Maturing 2042 [Member]
Debt Instrument [Line Items]
Long-term borrowings (in dollars)		$ 147
Corporate Debt Securities [Member] | Parent Company [Member] | Fixed-Rate Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate minimum		3.75%
Interest rate maximum		10.25%
Weighted-average interest rate		4.75%
Long-term borrowings (in dollars)	[2]	$ 2,073		2,066	[1]
Corporate Debt Securities [Member] | Parent Company [Member] | Fixed-Rate Retail Notes [Member]
Debt Instrument [Line Items]
Interest rate minimum		3.00%
Interest rate maximum		4.40%
Weighted-average interest rate		3.94%
Long-term borrowings (in dollars)		$ 77		39	[1]
Senior Notes [Member] | Discover Bank [Member] | Fixed-Rate Senior Bank Notes [Member]
Debt Instrument [Line Items]
Interest rate minimum		2.00%
Interest rate maximum		4.25%
Weighted-average interest rate		3.16%
Long-term borrowings (in dollars)	[2]	$ 5,128		5,115	[1]
Subordinated Debt [Member] | Discover Bank [Member] | Fixed-Rate Subordinated Bank Notes [Member]
Debt Instrument [Line Items]
Interest rate minimum		7.00%
Interest rate maximum		8.70%
Weighted-average interest rate		7.49%
Long-term borrowings (in dollars)		$ 695		$ 695	[1]
[1]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.
[2]	The Company uses interest rate swaps to hedge portions of these long-term borrowings against changes in fair value attributable to changes in London Interbank Offered Rate (“LIBOR”). Use of these interest rate swaps impacts carrying value of the debt.
[3]	Discover Card Execution Note Trust floating-rate asset-backed securities include issuances with the following interest rate terms: 1-month LIBOR + 18 to 45 basis points and 3-month LIBOR + 20 basis points as of March 31, 2016.
[4]	The Company uses interest rate swaps to manage its exposure to changes in interest rates related to future cash flows resulting from interest payments on a portion of these long-term borrowings. There is no impact on debt carrying value from use of these interest rate swaps. See Note 15: Derivatives and Hedging Activities.
[5]	Includes $302 million of senior notes maturing in 2031, $621 million of senior and subordinated notes maturing in 2036 and $147 million of senior notes maturing in 2042 as of March 31, 2016.
[6]	Repayment of this debt is dependent upon the timing of principal and interest payments on the underlying student loans. The dates shown represent final maturity dates.
[7]	SLC Private Student Loan Trusts floating-rate asset-backed securities include issuances with the following interest rate terms: 3-month LIBOR + 17 to 45 basis points, Prime rate + 75 to 100 basis points and 1-month LIBOR + 350 basis points as of March 31, 2016.
[8]	The Company acquired an interest rate swap related to the securitized debt assumed in the SLC transaction. The swap does not qualify for hedge accounting and has no impact on debt carrying value. See Note 15: Derivatives and Hedging Activities.

Long-Term Borrowings (Schedul68

Long-Term Borrowings (Schedule of Long-Term Borrowings Maturities) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	[1]
Debt Disclosure [Abstract]
2,016	$ 2,150
2,017	5,099
2,018	5,273
2,019	4,270
2,020	3,094
Thereafter	4,866
Total	$ 24,752	$ 24,650
[1]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Accumulated Other Comprehensi69

Accumulated Other Comprehensive Income (Schedule of Changes in Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period, net of tax	$ (160)	$ (138)
Net change in accumulated other comprehensive income (loss), net of tax	(12)	(23)
Accumulated other comprehensive income (loss), balance at end of period, net of tax	(172)	(161)
Unrealized Gain (Loss) on Available-for-Sale Investment Securities, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period, net of tax	0	23
Net change in accumulated other comprehensive income (loss), net of tax	14	0
Accumulated other comprehensive income (loss), balance at end of period, net of tax	14	23
(Loss) Gain on Cash Flow Hedges, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period, net of tax	(20)	(7)
Net change in accumulated other comprehensive income (loss), net of tax	(26)	(23)
Accumulated other comprehensive income (loss), balance at end of period, net of tax	(46)	(30)
Pension Plan Loss, Net of Tax [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period, net of tax	(140)	(154)
Net change in accumulated other comprehensive income (loss), net of tax	0	0
Accumulated other comprehensive income (loss), balance at end of period, net of tax	$ (140)	$ (154)

Accumulated Other Comprehensi70

Accumulated Other Comprehensive Income (Schedule of Other Comprehensive Income Before Reclassifications and Amounts Reclassified from AOCI) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Available-for-sale investment securities, net unrealized holding gain (loss) arising during the period, before tax	$ 23	$ 8
Available-for-sale investment securities, net unrealized holding gain (loss) arising during the period, tax benefit (expense)	(9)	(3)
Available-for-sale investment securities, net unrealized holding gain (loss) arising during the period, net of tax	14	5
Available-for-sale investment securities, amounts reclassified from AOCI, before tax	0	(8)
Available-for-sale investment securities, amounts reclassified from AOCI, tax benefit (expense)	0	3
Available-for-sale investment securities, amounts reclassified from AOCI, net of tax	0	(5)
Available-for-sale investment securities, net change, before tax	23	0
Available-for-sale investment securities, net change, tax benefit (expense)	(9)	0
Available-for-sale investment securities, net change, net of tax	14	0
Cash flow hedges, net unrealized gain (loss) arising during the period, before tax	(52)	(47)
Cash flow hedges, net unrealized gain (loss) arising during the period, tax benefit (expense)	21	17
Cash flow hedges, net unrealized gain (loss) arising during the period, net of tax	(31)	(30)
Cash flow hedges, amounts reclassified from AOCI, before tax	9	12
Cash flow hedges, amounts reclassified from AOCI, tax benefit (expense)	(4)	(5)
Cash flow hedges, amounts reclassified from AOCI, net of tax	5	7
Cash flow hedges, net change, before tax	(43)	(35)
Cash flow hedges, net change, tax benefit (expense)	17	12
Cash flow hedges, net change, net of tax	$ (26)	$ (23)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2016	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Change in income tax expense		$ 17
Change in effective income tax rate (in percent)		1.60%
Subsequent Event [Member] | Settlement with Taxing Authority [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Minimum reasonably possible reduction in the amount of unrecognized tax benefits	$ 337
Tax Adjustments, Settlements, and Unusual Provisions	$ 40

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Calculation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income before income tax expense	$ 914	$ 908
Income tax expense	$ 339	$ 322
Effective income tax rate (in percent)	37.10%	35.50%

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Basic and Diluted EPS ) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator:
Net income	$ 575	$ 586
Preferred stock dividends	(9)	(9)
Net income available to common stockholders	566	577
Income allocated to participating securities	(4)	(4)
Net income allocated to common stockholders	562	573
Income allocated to participating securities, diluted	(4)	(4)
Net income allocated to common stockholders, diluted	$ 562	$ 573
Denominator:
Weighted-average shares of common stock outstanding (in shares)	417	448
Basic earnings per common share (in dollars per share)	$ 1.35	$ 1.28
Diluted earnings per common share (in dollars per share)	$ 1.35	$ 1.28

Capital Adequacy (Narrative) (D

Capital Adequacy (Narrative) (Details)	Mar. 31, 2016
Regulatory Capital Requirements [Abstract]
Basel III minimum total capital ratio requirement	8.00%
Basel III minimum tier 1 capital ratio requirement	6.00%
Basel III minimum leverage ratio requirement	4.00%
Basel III minimum CET1 ratio requirement	4.50%

Capital Adequacy (Schedule of M

Capital Adequacy (Schedule of Minimum and Well-Capitalized Requirements) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Compliance with Regulatory Capital Requirements [Line Items]
Total capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	8.00%
Tier I capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	6.00%
Tier I capital to average assets, minimum capital requirements, ratio (in percent)	4.00%
CET1 capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	4.50%
Parent Company [Member]
Compliance with Regulatory Capital Requirements [Line Items]
Total capital to risk-weighted assets, actual amount	$ 12,463	$ 12,497	[1]
Total capital to risk-weighted assets, actual ratio (in percent)	16.80%	16.50%
Total capital to risk-weighted assets, minimum capital requirements, amount	$ 5,936	$ 6,052	[1]
Total capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	8.00%	8.00%
Total capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 7,421	$ 7,565	[1]
Total capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	10.00%	10.00%
Tier I capital to risk-weighted assets, actual amount	$ 11,153	$ 11,126
Tier I capital to risk-weighted assets, actual ratio (in percent)	15.00%	14.70%
Tier I capital to risk-weighted assets, minimum capital requirements, amount	$ 4,452	$ 4,539	[1]
Tier I capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	6.00%	6.00%
Tier I capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 5,936	$ 6,052	[1]
Tier I capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	8.00%	8.00%
Tier I capital to average assets, actual amount	$ 11,153	$ 11,126
Tier I capital to average assets, actual ratio (in percent)	12.80%	12.90%
Tier I capital to average assets, minimum capital requirements, amount	$ 3,493	$ 3,446	[1]
Tier I capital to average assets, minimum capital requirements, ratio (in percent)	4.00%	4.00%
Tier I capital to average assets, capital requirements to be classified as well-capitalized, amount	$ 4,366	$ 4,307	[1]
Tier I capital to average assets, capital requirements to be classified as well-capitalized, ratio (in percent)	5.00%	5.00%
Parent Company [Member] | Transition [Member]
Compliance with Regulatory Capital Requirements [Line Items]
CET1 capital to risk-weighted assets, actual amount	$ 10,593	$ 10,566
CET1 capital to risk-weighted assets, actual ratio (in percent)	14.30%	14.00%	[1]
CET1 capital to risk-weighted assets, minimum capital requirements, amount	$ 3,339	$ 3,404	[1]
CET1 capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	4.50%	4.50%
CET1 capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 4,823	$ 4,917	[1]
CET1 capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	6.50%	6.50%
Discover Bank [Member]
Compliance with Regulatory Capital Requirements [Line Items]
Total capital to risk-weighted assets, actual amount	$ 12,008	$ 11,905	[1]
Total capital to risk-weighted assets, actual ratio (in percent)	16.40%	15.90%
Total capital to risk-weighted assets, minimum capital requirements, amount	$ 5,876	$ 5,991	[1]
Total capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	8.00%	8.00%
Total capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 7,345	$ 7,488	[1]
Total capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	10.00%	10.00%
Tier I capital to risk-weighted assets, actual amount	$ 10,061	$ 9,941
Tier I capital to risk-weighted assets, actual ratio (in percent)	13.70%	13.30%
Tier I capital to risk-weighted assets, minimum capital requirements, amount	$ 4,407	$ 4,493	[1]
Tier I capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	6.00%	6.00%
Tier I capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 5,876	$ 5,991	[1]
Tier I capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	8.00%	8.00%
Tier I capital to average assets, actual amount	$ 10,061	$ 9,941
Tier I capital to average assets, actual ratio (in percent)	11.60%	11.70%	[1]
Tier I capital to average assets, minimum capital requirements, amount	$ 3,459	$ 3,410	[1]
Tier I capital to average assets, minimum capital requirements, ratio (in percent)	4.00%	4.00%
Tier I capital to average assets, capital requirements to be classified as well-capitalized, amount	$ 4,323	$ 4,263	[1]
Tier I capital to average assets, capital requirements to be classified as well-capitalized, ratio (in percent)	5.00%	5.00%
Discover Bank [Member] | Transition [Member]
Compliance with Regulatory Capital Requirements [Line Items]
CET1 capital to risk-weighted assets, actual amount	$ 10,061	$ 9,941
CET1 capital to risk-weighted assets, actual ratio (in percent)	13.70%	13.30%
CET1 capital to risk-weighted assets, minimum capital requirements, amount	$ 3,305	$ 3,370	[1]
CET1 capital to risk-weighted assets, minimum capital requirements, ratio (in percent)	4.50%	4.50%
CET1 capital to risk-weighted assets, capital requirements to be classified as well-capitalized, amount	$ 4,774	$ 4,867	[1]
CET1 capital to risk-weighted assets, capital requirements to be classified as well-capitalized, ratio (in percent)	6.50%	6.50%
[1]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Commitments, Contingencies an76

Commitments, Contingencies and Guarantees (Narrative) (Details) $ in Billions	3 Months Ended
	Mar. 31, 2016USD ($)
Commitments, Contingencies and Guarantees [Line Items]
Period for disabling a counterparty settlement	1 month
Commitments to Extend Credit [Member]
Commitments, Contingencies and Guarantees [Line Items]
Unused commitments to extend credit for loans	$ 182.8

Commitments, Contingencies an77

Commitments, Contingencies and Guarantees (Schedule of Lease Commitments) (Details) $ in Millions	Mar. 31, 2016USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,016	$ 11
2,017	12
2,018	11
2,019	9
2,020	7
Thereafter	34
Total minimum lease payments	$ 84

Commitments, Contingencies an78

Commitments, Contingencies and Guarantees (Schedule of Maximum Potential Counterparty Exposures Related to Settlement Guarantees) (Details) $ in Millions	Mar. 31, 2016USD ($)
Merchant Guarantee [Member] | Diners Club [Member]
Guarantor Obligations [Line Items]
Maximum potential counterparty exposures to settlement guarantees	$ 142
ATM Guarantee [Member] | PULSE [Member]
Guarantor Obligations [Line Items]
Maximum potential counterparty exposures to settlement guarantees	$ 1

Commitments, Contingencies an79

Commitments, Contingencies and Guarantees (Schedule of Merchant Chargeback Guarantee) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Merchant Chargebacks [Member]
Loss Contingencies [Line Items]
Aggregate sales transaction volume	[1]	$ 31,281	$ 29,498
[1]	Represents period transactions processed on the Discover Network for which a potential liability exists that, in aggregate, can differ from credit card sales volume.

Commitments, Contingencies an80

Commitments, Contingencies and Guarantees (Schedule of Settlement Withholdings and Escrow Deposits) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Commitments Contingencies and Guarantees [Abstract]
Settlement withholdings and escrow deposits	$ 6	$ 7

Litigation and Regulatory Mat81

Litigation and Regulatory Matters (Narrative) (Details) - USD ($)	Jul. 22, 2015	Mar. 31, 2015	Mar. 31, 2016	Jul. 09, 2015
Loss Contingencies [Line Items]
Litigation expense		$ 23,000,000
TCPA statutory damages for each violation				$ 500
TCPA statutory damages for each willful violation				$ 1,500
Unfavorable Regulatory Action [Member] | CFPB Consent Order [Member]
Loss Contingencies [Line Items]
Amount of redress for CFPB consent order	$ 16,000,000
Amount of civil money penalty for CFPB consent order	$ 2,500,000
Pending and Threatened Litigation [Member]
Loss Contingencies [Line Items]
Aggregate range of reasonably possible losses			$ 160,000,000

Fair Value Measurements and D82

Fair Value Measurements and Disclosures (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities, par value	$ 1,100
Available for sale securities, weighted average coupon rate (in percent)	2.81%
Available for sale securities, weighted average remaining maturity (in years)	3 years
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset transfers from level 1 to level 2 within the fair value hierarchy	$ 0	$ 0
Asset transfers from level 2 to level 1 within the fair value hierarchy	0	0
Liability transfers from level 1 to level 2 within the fair value hierarchy	0	0
Liability transfers from level 2 to level 1 within the fair value hierarchy	$ 0	$ 0

Fair Value Measurements and D83

Fair Value Measurements and Disclosures (Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	$ 2,824	$ 2,963
Other Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments, assets, fair value	58	22
Derivative financial instruments, liabilities, fair value	78	38
U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,180	1,272
U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	492	494
Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,152	1,197
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,672	1,766
Level 1 [Member] | Other Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments, assets, fair value	0	0
Derivative financial instruments, liabilities, fair value	0	0
Level 1 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,180	1,272
Level 1 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	492	494
Level 1 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,152	1,197
Level 2 [Member] | Other Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments, assets, fair value	58	22
Derivative financial instruments, liabilities, fair value	78	38
Level 2 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 2 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 2 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	1,152	1,197
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 3 [Member] | Other Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments, assets, fair value	0	0
Derivative financial instruments, liabilities, fair value	0	0
Level 3 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 3 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	0	0
Level 3 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investment securities, fair value	$ 0	$ 0

Fair Value Measurements and D84

Fair Value Measurements and Disclosures (Schedule of Financial Instruments Measured at Other Than Fair Value) (Details) - USD ($) $ in Millions		Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities	[1]	$ 135	$ 122
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		135	122
Cash and cash equivalents		12,135	9,572
Restricted cash		1,010	99
Net loan receivables		69,473	71,455
Accrued interest receivables		666	660
Deposits		48,775	47,714
Accrued interest payables		172	158
Fair Value, Measurements, Nonrecurring [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		16,980	16,854
Fair Value, Measurements, Nonrecurring [Member] | Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		8,444	8,355
Fair Value, Measurements, Nonrecurring [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		1	1
Fair Value, Measurements, Nonrecurring [Member] | States and Political Subdivisions of States [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		5	7
Fair Value, Measurements, Nonrecurring [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		129	114
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		132	121
Cash and cash equivalents		12,135	9,572
Restricted cash		1,010	99
Net loan receivables		68,399	70,516
Accrued interest receivables		666	660
Deposits		48,465	47,531	[2]
Accrued interest payables		172	158
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		16,779	16,735	[2]
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member] | Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		7,973	7,915	[2]
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		1	1
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member] | States and Political Subdivisions of States [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		5	7
Fair Value, Measurements, Nonrecurring [Member] | Carrying Value [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		126	113
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		1	1
Cash and cash equivalents		12,135	9,572
Restricted cash		1,010	99
Net loan receivables		0	0
Accrued interest receivables		0	0
Deposits		0	0
Accrued interest payables		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		1	1
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | States and Political Subdivisions of States [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		134	121
Cash and cash equivalents		0	0
Restricted cash		0	0
Net loan receivables		0	0
Accrued interest receivables		666	660
Deposits		48,775	47,714
Accrued interest payables		172	158
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		15,849	15,634
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		8,444	8,355
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | States and Political Subdivisions of States [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		5	7
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		129	114
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Cash and cash equivalents		0	0
Restricted cash		0	0
Net loan receivables		69,473	71,455
Accrued interest receivables		0	0
Deposits		0	0
Accrued interest payables		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		1,131	1,220
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term borrowings		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | U.S. Treasury Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | States and Political Subdivisions of States [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		0	0
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Residential Mortgage-Backed Securities - Agency [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity investment securities		$ 0	$ 0
[1]	Held-to-maturity investment securities are reported at amortized cost.
[2]	Upon adoption of ASU 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, certain balances as of December 31, 2015 have been restated to reflect the classification of debt issuance costs as a direct deduction of the related liability. See Note 1: Background and Basis of Presentation for additional information.

Derivatives and Hedging Activ85

Derivatives and Hedging Activities (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)
Derivative [Line Items]
Cash collateral posted	$ 4
Additional collateral	69
Interest Expense [Member]
Derivative [Line Items]
Cash flow hedge loss to be reclassified to earnings within twelve months	$ 31
Securitized Debt [Member]
Derivative [Line Items]
Initial maximum period for cash flow hedges (in years)	5 years
Deposits [Member]
Derivative [Line Items]
Initial maximum period for cash flow hedges (in years)	7 years

Derivatives and Hedging Activ86

Derivatives and Hedging Activities (Schedule of Fair Value and Outstanding Notional Amounts of Derivative Instruments and Related Collateral Balances) (Details) € in Millions, £ in Millions, SGD in Millions, $ in Millions		Mar. 31, 2016USD ($)transactions		Mar. 31, 2016SGDtransactions	Mar. 31, 2016EUR (€)transactions	Mar. 31, 2016GBP (£)transactions	Dec. 31, 2015USD ($)transactions		Dec. 31, 2015SGDtransactions	Dec. 31, 2015EUR (€)transactions	Dec. 31, 2015GBP (£)transactions
Derivatives, Fair Value [Line Items]
Derivative assets	[1]	$ 58					$ 22
Collateral held, derivative assets	[2]	(21)					(8)
Total net derivative assets		37					14
Derivative liabilities	[1]	78					38
Collateral posted, derivative liabilities	[2]	(63)					(33)
Total net derivative liabilities		15					5
Designated as Hedges [Member] | Cash Flow Hedge [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 4,100					4,100
Derivative, number of outstanding derivative contracts (in transactions) | transactions		8		8	8	8
Derivative assets		$ 0					0
Derivative liabilities		78					35
Designated as Hedges [Member] | Fair Value Hedge [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 4,854					4,110
Derivative, number of outstanding derivative contracts (in transactions) | transactions		105		105	105	105
Derivative assets		$ 58					22
Derivative liabilities		0					3
Not Designated as Hedges [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount	[3]	$ 198					217
Derivative, number of outstanding derivative contracts (in transactions) | transactions	[3]	1		1	1	1
Derivative assets	[3]	$ 0					0
Derivative liabilities	[3]	0					0
Not Designated as Hedges [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 32	[4]	SGD 1	€ 19	£ 7	32	[4]	SGD 1	€ 19	£ 7
Derivative, number of outstanding derivative contracts (in transactions) | transactions		6		6	6	6
Derivative assets		$ 0					0
Derivative liabilities		0					0
Not Designated as Hedges [Member] | When-Issued Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 36					$ 52
Derivative, number of outstanding derivative contracts (in transactions) | transactions		1		1	1	1	1		1	1	1
[1]	In addition to the derivatives disclosed in the table, the Company enters into forward contracts to purchase when-issued mortgage-backed securities as part of its community reinvestment initiatives. At March 31, 2016, the Company had one outstanding contract with a notional amount of $36 million and immaterial fair value. At December 31, 2015, the Company had one outstanding contract with a notional amount of $52 million and immaterial fair value.
[2]	Collateral amounts, which consist of both cash and investment securities, are limited to the related derivative asset/liability balance and do not include excess collateral received/pledged.
[3]	Interest rate swaps not designated as hedges do not have associated master netting arrangements.
[4]	The foreign exchange forward contracts have notional amounts of EUR 19 million, GBP 7 million and SGD 1 million as of March 31, 2016, and notional amounts of EUR 19 million, GBP 7 million and SGD 1 million as of December 31, 2015.

Derivatives and Hedging Activ87

Derivatives and Hedging Activities (Schedule of Impact of the Derivative Instruments on Income and Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Designated as Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on derivatives	$ 0	$ (3)
Designated as Hedges [Member] | Cash Flow and Net Investment Hedges [Member] | Interest Rate Swaps [Member] | Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total loss recognized in OCI after amounts reclassified into earnings, pre-tax	(43)	(35)
Designated as Hedges [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified from OCI into income	(9)	(12)
Designated as Hedges [Member] | Fair Value Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Adjustments - ineffectiveness	31	5
Adjustments - other	9	8
Gain on interest rate swaps	40	13
Designated as Hedges [Member] | Fair Value Hedges [Member] | Hedged Item [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Adjustments - ineffectiveness	(29)	(3)
Adjustments - other	(2)	(1)
Loss on hedged item	(31)	(4)
Not Designated as Hedges [Member] | Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on derivatives	$ (1)	49	[1]
Not Designated as Hedges [Member] | Forward Contracts [Member] | Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on derivatives		2
Not Designated as Hedges [Member] | Interest Rate Lock Commitments [Member] | Other Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on derivatives		$ 44
[1]	Amount as of March 31, 2015 includes $2 million gain on forward delivery contracts and $44 million gain on interest rate lock commitments related to the mortgage loan business that was closed during 2015. See Note 2: Business Dispositions.

Segment Disclosures (Narrative)

Segment Disclosures (Narrative) (Details)	3 Months Ended
	Mar. 31, 2016segment
Segment Reporting [Abstract]
Number of reportable segments (in number of segments)	2

Segment Disclosures (Schedule o

Segment Disclosures (Schedule of Segment Disclosures) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Interest income	$ 2,084	$ 1,929
Interest expense	334	300
Net interest income	1,750	1,629
Provision for loan losses	424	390
Other income	474	542
Other expense	886	873
Income before income tax expense	914	908
Other [Member]
Segment Reporting Information [Line Items]
Interest income	28	21
Credit Card Loans [Member]
Segment Reporting Information [Line Items]
Interest income	1,733	1,606
Provision for loan losses	362	337
Total Other Loans [Member] | Private Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	107	90
Total Other Loans [Member] | Personal Loans [Member]
Segment Reporting Information [Line Items]
Interest income	167	152
Provision for loan losses	44	31
PCI Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	49	60
Provision for loan losses	0	0
Operating Segments [Member] | Direct Banking [Member]
Segment Reporting Information [Line Items]
Interest income	2,084	1,929
Interest expense	334	300
Net interest income	1,750	1,629
Provision for loan losses	423	388
Other income	406	468
Other expense	851	828
Income before income tax expense	882	881
Operating Segments [Member] | Direct Banking [Member] | Other [Member]
Segment Reporting Information [Line Items]
Interest income	28	21
Operating Segments [Member] | Direct Banking [Member] | Credit Card Loans [Member]
Segment Reporting Information [Line Items]
Interest income	1,733	1,606
Operating Segments [Member] | Direct Banking [Member] | Total Other Loans [Member] | Private Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	107	90
Operating Segments [Member] | Direct Banking [Member] | Total Other Loans [Member] | Personal Loans [Member]
Segment Reporting Information [Line Items]
Interest income	167	152
Operating Segments [Member] | Direct Banking [Member] | PCI Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	49	60
Operating Segments [Member] | Payment Services [Member]
Segment Reporting Information [Line Items]
Interest income	0	0
Interest expense	0	0
Net interest income	0	0
Provision for loan losses	1	2
Other income	68	74
Other expense	35	45
Income before income tax expense	32	27
Operating Segments [Member] | Payment Services [Member] | Other [Member]
Segment Reporting Information [Line Items]
Interest income	0	0
Operating Segments [Member] | Payment Services [Member] | Credit Card Loans [Member]
Segment Reporting Information [Line Items]
Interest income	0	0
Operating Segments [Member] | Payment Services [Member] | Total Other Loans [Member] | Private Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	0	0
Operating Segments [Member] | Payment Services [Member] | Total Other Loans [Member] | Personal Loans [Member]
Segment Reporting Information [Line Items]
Interest income	0	0
Operating Segments [Member] | Payment Services [Member] | PCI Student Loans [Member]
Segment Reporting Information [Line Items]
Interest income	$ 0	$ 0