Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Related Parties
-URI http://asc.fasb.org/extlink&oid=16382449

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Commitments and Contingencies (Details) $ in Millions	3 Months Ended	9 Months Ended
Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jan. 31, 2016 employee	Aug. 31, 2015 shareholder
Shareholder Derivative Action
Loss Contingencies [Line Items]
Number of shareholders commencing punitive derivative action \| shareholder				2
CME Group \| S&P DJ Indices
Loss Contingencies [Line Items]
Revenues earned under license agreement \| $	$ 18	$ 56
Noncontrolling interest ownership by noncontrolling owners (as a percent)	27.00%	27.00%
S&P Global Ratings \| Shareholder Derivative Action
Loss Contingencies [Line Items]
Number of former employees named as defendants \| employee			9