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, 2016	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amortization of initial payments for new contracts	$ 15	$ 11
Amortization related to equity method investments	$ 9	$ 15