Loans and ACL - Collectively Evaluated for Impairment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Recorded Investment	$ 147,329	$ 142,044
Related ALLL	1,383	1,319
Commercial | Commercial and industrial
Recorded Investment	61,629	58,804
Related ALLL	521	494
Commercial | CRE
Recorded Investment	20,960	21,173
Related ALLL	181	154
Commercial | Lease financing
Recorded Investment	2,015	1,910
Related ALLL	11	9
Retail | Residential mortgage
Recorded Investment	30,539	27,914
Related ALLL	164	143
Retail | Direct
Recorded Investment	11,517	11,815
Related ALLL	92	98
Retail | Indirect
Recorded Investment	17,099	16,935
Related ALLL	299	296
Revolving credit
Recorded Investment	3,104	2,842
Related ALLL	106	97
PCI
Recorded Investment	466	651
Related ALLL	$ 9	$ 28