For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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)
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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.

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No definition available.

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Segment and Geographic Information - Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,374	$ 1,324	$ 1,342	$ 1,273	$ 1,290	$ 1,263	$ 1,302	$ 1,196	$ 5,313	$ 5,051	$ 4,702
Long-lived Assets	4,730				2,665				4,730	2,665
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,202	2,911	2,723
Long-lived Assets	4,198				2,117				4,198	2,117
European region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,265	1,316	1,226
Long-lived Assets	419				430				419	430
Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									566	528	483
Long-lived Assets	63				54				63	54
Rest of the world [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									280	296	$ 270
Long-lived Assets	$ 50				$ 64				$ 50	$ 64
Geographic Concentration Risk [Member] \| Revenue [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									100.00%	100.00%	100.00%
Geographic Concentration Risk [Member] \| Revenue [Member] \| United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									60.00%	58.00%	58.00%
Geographic Concentration Risk [Member] \| Revenue [Member] \| European region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									24.00%	26.00%	26.00%
Geographic Concentration Risk [Member] \| Revenue [Member] \| Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									11.00%	10.00%	10.00%
Geographic Concentration Risk [Member] \| Revenue [Member] \| Rest of the world [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									5.00%	6.00%	6.00%
Geographic Concentration Risk [Member] \| Long-lived Assets [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									100.00%	100.00%
Geographic Concentration Risk [Member] \| Long-lived Assets [Member] \| United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									89.00%	80.00%
Geographic Concentration Risk [Member] \| Long-lived Assets [Member] \| European region [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									9.00%	16.00%
Geographic Concentration Risk [Member] \| Long-lived Assets [Member] \| Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									1.00%	2.00%
Geographic Concentration Risk [Member] \| Long-lived Assets [Member] \| Rest of the world [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk									1.00%	2.00%