Name:	dfs_AvailableForSaleSecuritiesWeightedAverageCouponRate
Namespace Prefix:	dfs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The weighted average remianing maturity of available for sale investment securities.

No definition available.

Name:	dfs_AvailableForSaleSecuritiesWeightedAverageRemainingMaturity
Namespace Prefix:	dfs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The par value of credit card asset backed securities, which are included in available-for-sale investments and classified as Level 2 within the fair value hierarchy.

No definition available.

Name:	dfs_AvailableForSaleSecurityParValue
Namespace Prefix:	dfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.