Deposits - Noninterest and Interest-bearing (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
U.S. offices
Noninterest-bearing	$ 374,603	$ 393,645
Interest-bearing (included $16,526 and $14,947 at fair value)	814,988	793,618
Total deposits in U.S. offices	1,189,591	1,187,263
Non-U.S. offices
Noninterest-bearing	19,127	15,576
Interest-bearing (included $3,974 and $6,374 at fair value)	250,044	241,143
Total deposits in non-U.S. offices	269,171	256,719
Total deposits	1,458,762	1,443,982
Fair value
U.S. offices
Interest-bearing, fair value	16,526	14,947
Non-U.S. offices
Interest-bearing, fair value	$ 3,974	$ 6,374