Income Taxes - Significant Components of Deferred Tax Assets and Liabilities Included in "Accrued Income and Other Assets" and "Accrued Expense and Other Liabilities" (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Allowance for loan and lease losses	$ 232	$ 233
Employee benefits	170	147
Net unrealized securities losses	144	138
Federal net operating losses and credits	34	205
Fair value adjustments	41	63
Non-tax accruals	80	89
State net operating losses and credits	3	7
Other	221	223
Gross deferred tax assets	925	1,105
Less: Valuation Allowance	11	15
Total deferred tax assets	914	1,090
Leasing transactions	531	588
Other	161	182
Total deferred tax liabilities	692	770
Net deferred tax assets (liabilities)	$ 222	$ 320