Interest Income and Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income
Investment securities									$ 1,744	$ 1,334	$ 1,142
Loans									4,249	3,298	2,724
Securities purchased under agreements to resell and Securities borrowed									1,976	169	(374)
Trading assets, net of Trading liabilities									2,392	2,029	2,131
Customer receivables and Other									3,531	2,167	1,393
Total Interest income									13,892	8,997	7,016
Interest expense
Deposits									1,255	187	83
Borrowings									5,031	4,285	3,606
Securities sold under agreements to repurchase and Securities loaned									1,898	1,237	977
Customer payables and Other									1,902	(12)	(1,348)
Total interest expense									10,086	5,697	3,318
Net interest	$ 989	$ 936	$ 906	$ 975	$ 995	$ 783	$ 751	$ 771	$ 3,806	$ 3,300	$ 3,698