Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Amounts Associated with Amortization of Initial Payments for New Contracts and Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amortization of initial payments for new contracts	$ 16	$ 14	$ 47	$ 38
Amortization related to equity method investments	$ 12	$ 15	$ 33	$ 45