Employee Benefits - Schedule of expense recognized in Compensation and benefit in the Consolidated Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Contribution Savings Plans
U.S.	$ 133	$ 123	$ 123
U.K.	42	42	45
Other	25	30	18
Expense recognized for defined contribution savings plans	$ 200	$ 195	$ 186