Certain Transfers of Financial Assets and Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
		Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other			$ 12	$ 19	$ 21
Total assets		$ 204,875	204,875	190,817
Total liabilities		181,257	181,257	167,380
Long-term Debt	[1]	11,748	11,748	8,462
Potential loss on securitization of loans		512	512
Derivative Asset, Notional Amount		133,395	$ 133,395	123,025
Document Period End Date			Dec. 31, 2016
Trading assets	[2]	6,067	$ 6,067	6,119
Other Assets		6,405	6,405	5,582
Affordable Housing Tax Credits and Other Tax Benefits, Amount			92	68	66
Amortization Method Qualified Affordable Housing Project Investments, Amortization			87	66	61
Amortization of Intangible Assets	[3]		9	8
Amortization			49	40	25
Affordable Housing Investment [Member]
Properties sold, carrying value				72
Affordable Housing [Member]
Gain (Loss) on Sale of Properties				19
Variable Interest Entity, Not Primary Beneficiary [Member] | Community Development Investments [Member]
Investment Tax Credit			64	53	33
Amortization of Intangible Assets			46	35	19
Amortization					14
Variable Interest Entity, Primary Beneficiary [Member]
Long-term Debt		222	222	259
Residential Mortgage [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Loans and Leases Receivable, Gain (Loss) on Sales, Net			331	232	224
Transferor's Interests in Transferred Financial Assets, Fair Value		30	30	38
Total assets		203	203	241
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		30	30	37
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets		185	185	525
Total liabilities		159	159	482
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Loans Receivable, Net		225	225	262
Long-term Debt		$ 222	$ 222	259
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Maximum [Member]
Government Guarantee Percent		100.00%	100.00%
Total Return Swap [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Derivative Asset, Notional Amount		$ 2,100	$ 2,100	2,200
Trading assets		2,100	2,100	2,200
Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets		1,700	1,700	1,600
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		562	562	321
Real Estate Variable Interest Entity Borrowings		200	200	132
Limited Partner [Member] | Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Other Assets		780	780	672
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		1,076	1,076	1,064
Loans issued by the Company to the limited partnerships		306	$ 306	268
Other Expense [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Community Development Investments [Member]
Amortization					$ 5
Consumer Portfolio Segment [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Proceeds from Securitizations of Consumer Loans				1,000
Principal Amount Outstanding on Loans Securitized or Asset-backed Financing Arrangement				$ 1,000
Pillar Financial [Member] | Commercial Portfolio Segment [Member]
Principal Amount of Loans Transferred to Securitization		$ 19

[1] Includes debt of consolidated VIEs of $222 million and $259 million at December 31, 2016 and December 31, 2015, respectively.

[2] Includes trading securities pledged as collateral where counterparties have the right to sell or repledge the collateral of $1,437 million and $1,377 million at December 31, 2016 and December 31, 2015, respectively.

[3] Does not include expense associated with non-qualified community development investments. See Note 10, "Certain Transfers of Financial Assets and Variable Interest Entities," for additional information.