Deposits - Noninterest and Interest-bearing (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
U.S. offices
Noninterest-bearing	$ 385,741	$ 393,645
Interest-bearing (included $15,542 and $14,947 at fair value)	819,454	793,618
Total deposits in U.S. offices	1,205,195	1,187,263
Non-U.S. offices
Noninterest-bearing	16,602	15,576
Interest-bearing (included $4,154 and $6,374 at fair value)	230,325	241,143
Total deposits in non-U.S. offices	246,927	256,719
Total deposits	1,452,122	1,443,982
Fair value
U.S. offices
Interest-bearing, fair value	15,542	14,947
Non-U.S. offices
Interest-bearing, fair value	$ 4,154	$ 6,374