Fair Value - Schedule of Fair Value Measurements, Liabilities, Using Significant Unobservable Inputs (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 50	$ 5	$ 83
Total realized and unrealized (gains) losses recorded in revenue	(3)	5	24
Issuances	1		19
Settlements	(26)	(10)	(104)
Fair value, end of period	22	0	22
Change in unrealized (gains) losses related to financial instruments held	1	0	(2)
Derivative instruments, liabilities | Accrued expenses and other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	50	5	83
Total realized and unrealized (gains) losses recorded in revenue	(3)	5	24
Issuances	1		19
Settlements	(26)	(10)	(104)
Fair value, end of period	22	0	22
Change in unrealized (gains) losses related to financial instruments held	1	0	(2)
Foreign exchange contracts | Accrued expenses and other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	50	5	74
Total realized and unrealized (gains) losses recorded in revenue	(3)	5	24
Issuances	1		19
Settlements	(26)	(10)	(95)
Fair value, end of period	22	0	22
Change in unrealized (gains) losses related to financial instruments held	1	$ 0	(2)
Other | Accrued expenses and other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period			9
Total realized and unrealized (gains) losses recorded in revenue			0
Issuances			0
Settlements			(9)
Fair value, end of period	$ 0		0
Change in unrealized (gains) losses related to financial instruments held			$ 0