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
	Mar. 31, 2017	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amortization of initial payments for new contracts	$ 19	$ 15
Amortization related to equity method investments	$ 11	$ 9