Loans and ACL - Collectively Evaluated for Impairment (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Recorded Investment	$ 151,024	$ 147,329
Related ALLL	1,430	1,383
Commercial | Commercial and industrial
Recorded Investment	63,383	61,629
Related ALLL	546	521
Commercial | CRE
Recorded Investment	20,667	20,960
Related ALLL	197	181
Commercial | Lease financing
Recorded Investment	2,201	2,015
Related ALLL	10	11
Retail | Residential mortgage
Recorded Investment	31,842	30,539
Related ALLL	168	164
Retail | Direct
Recorded Investment	11,427	11,517
Related ALLL	94	92
Retail | Indirect
Recorded Investment	17,873	17,099
Related ALLL	298	299
Revolving credit
Recorded Investment	3,210	3,104
Related ALLL	109	106
PCI
Recorded Investment	421	466
Related ALLL	$ 8	$ 9