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.

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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.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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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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Segment and Geographic Information - Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 1,735	$ 1,689	$ 1,704	$ 1,571	$ 1,536	$ 1,546	$ 1,609	$ 1,567	$ 6,699	$ 6,258	$ 6,063
Long-lived Assets	5,406				5,429				5,406	5,429
U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									3,949	3,750	3,658
Long-lived Assets	4,946				5,019				4,946	5,019
European region
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									1,681	1,543	1,473
Long-lived Assets	323				317				323	317
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									715	647	594
Long-lived Assets	93				51				93	51
Rest of the world
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									354	318	$ 338
Long-lived Assets	$ 44				$ 42				$ 44	$ 42
Geographic Concentration Risk \| Revenue
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									100.00%	100.00%	100.00%
Geographic Concentration Risk \| Revenue \| U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									59.00%	60.00%	60.00%
Geographic Concentration Risk \| Revenue \| European region
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									25.00%	25.00%	24.00%
Geographic Concentration Risk \| Revenue \| Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									11.00%	10.00%	10.00%
Geographic Concentration Risk \| Revenue \| Rest of the world
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									5.00%	5.00%	6.00%
Geographic Concentration Risk \| Long-lived Assets
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									100.00%	100.00%
Geographic Concentration Risk \| Long-lived Assets \| U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									91.00%	92.00%
Geographic Concentration Risk \| Long-lived Assets \| European region
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									6.00%	6.00%
Geographic Concentration Risk \| Long-lived Assets \| Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									2.00%	1.00%
Geographic Concentration Risk \| Long-lived Assets \| Rest of the world
Revenues from External Customers and Long-Lived Assets [Line Items]
Concentration risk (as a percent)									1.00%	1.00%