Fair Value Measurements - Contingent Consideration (Details) - USD ($)		3 Months Ended
	Jul. 29, 2016	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other revenues		$ 17,000,000	$ 53,000,000
Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent Consideration Commission payable		0
Paid [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent Consideration Commission payable		10,000,000
Cumulative Paid [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent Consideration Commission payable		30,000,000
Lattice
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent Consideration	$ 60,000,000
Contingent Consideration Payment Period	4 years
Other revenues		$ 12,000,000
Lattice | Contingent Obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assumption for Fair Value of Assets or Liabilities that relate to Transferor's Continuing Involvement, Discount Rate		11.80%
AUM Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination,Contingent Consideration, Liability, Measurement Input Amount				$ 3,000,000,000