Segments (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment	Sep. 30, 2014 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| segment			1
Net transaction revenues	$ 1,659	$ 1,703	$ 5,012	$ 5,144
Marketing services and other revenues	440	447	1,258	1,323
Net revenues	$ 2,099	$ 2,150	$ 6,270	$ 6,467

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration