Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
ALLL	$ 374	$ 359
Postretirement plans	360	311
Net unrealized loss on AFS securities	156	112
Equity-based compensation	82	66
Reserves and expense accruals	203	114
Partnerships	77	70
Other	158	160
Total deferred tax assets	1,410	1,192
Deferred tax liabilities:
Prepaid pension plan expense	453	436
MSRs	248	234
Lease financing	376	366
Loan fees and expenses	169	114
Identifiable intangible assets	183	163
Other	82	31
Total deferred tax liabilities	1,511	1,344
Net deferred tax asset (liability)	$ (101)	$ (152)