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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	$ (8)	$ 14	$ (18)	$ 13
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	(4)	3	(4)	(7)
Compensation and Benefits [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	0	1	(2)	6
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	0	1	1	1
Other General Expenses [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	(2)	3	(5)	1
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	(1)	(1)	(1)	(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):	(1)	(2)	(1)	(4)
Other Income (Expense) [Member]
Derivative [Line Items]
Gain (Loss) Recognized in Accumulated Other Comprehensive Loss:	(6)	10	(11)	6
Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion):	$ (2)	$ 5	$ (3)	$ (3)