Income Taxes - Significant Components of Deferred Tax Assets and Liabilities Included in "Accrued Income and Other Assets" and "Accrued Expense and Other Liabilities" (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Allowance for loan and lease losses	$ 373	$ 327
Employee benefits	276	268
Net unrealized securities losses	146	48
Federal net operating losses and credits	130	88
Fair value adjustments	136	0
Non-tax accruals	150	81
State net operating losses and credits	15	5
Other	236	260
Gross deferred tax assets	1,462	1,077
Less: Valuation Allowance	26	0
Total deferred tax assets	1,436	1,077
Leasing transactions	728	651
Fair Value Adjustments	0	2
Other	101	125
Total deferred tax liabilities	829	778
Net deferred tax assets (liabilities)	$ 607	$ 299