Derivatives and Hedging - Schedule of amounts of derivative gains (losses) recognized in the Consolidated Financial Statements (Details) - Cash Flow Hedging [Member] - Foreign exchange contracts [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	$ (1)	$ (14)	$ (19)	$ (1)
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	(2)	0	(6)	(7)
Compensation and Benefits [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	10	(8)	8	(2)
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	1	2	2	3
Other General Expenses [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	(4)	(2)	(9)	(1)
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	(1)	0	(2)	(1)
Interest Expense [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	0	0	0	0
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	0	(2)	(1)	(6)
Other Income (Expense) [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	(7)	(4)	(18)	2
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	$ (2)	$ 0	$ (5)	$ (3)