Certain Transfers of Financial Assets and Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other		$ 3	$ 4	$ 5	$ 8
Total assets		198,892		198,892		$ 190,817
Total liabilities		174,428		174,428		167,380
Long-term Debt	[1]	12,264		12,264		8,462
Potential loss on securitization of loans		652		652
Derivative Asset, Notional Amount		136,166		136,166		123,025
Trading assets	[2]	6,850		6,850		6,119
Other Assets		6,205		6,205		5,582
Affordable Housing Tax Credits and Other Tax Benefits, Amount		19	15	38	29
Amortization Method Qualified Affordable Housing Project Investments, Amortization		19	14	38	28
Amortization of Intangible Assets	[3]			4	3
Affordable Housing Investment [Member]
Properties sold, carrying value			9	0	72
Affordable Housing [Member]
Gain (Loss) on Sale of Properties			1		19
Variable Interest Entity, Not Primary Beneficiary [Member] | Community Development Investments [Member]
Investment Tax Credit		15	9	29	18
Amortization of Intangible Assets		11	5	20	10
Variable Interest Entity, Primary Beneficiary [Member]
Long-term Debt		240		240		259
Residential Mortgage [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Loans and Leases Receivable, Gain (Loss) on Sales, Net		90	46	158	61
Transferor's Interests in Transferred Financial Assets, Fair Value		34		34		38
Total assets		226		226		241
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets		445		445		525
Total liabilities		404		404		482
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Preference Shares [Member]
Total assets		3		3		2
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Senior Subordinated Notes [Member]
Total assets		4		4		8
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Loans Receivable, Net		243		243		262
Long-term Debt		$ 240		$ 240		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		$ 2,200		$ 2,200		2,200
Trading assets		2,200		2,200		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		402		402		321
Real Estate Variable Interest Entity Borrowings		136		136		132
Limited Partner [Member] | Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Other Assets		815		815		672
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		1,179		1,179		1,064
Loans issued by the Company to the limited partnerships		$ 290		$ 290		$ 268
Consumer Portfolio Segment [Member] | Asset-backed Securities, Securitized Loans and Receivables [Member]
Principal Amount Outstanding on Loans Securitized or Asset-backed Financing Arrangement			1,000		$ 1,000
Proceeds from Securitizations of Consumer Loans			$ 1,000

[1] Includes debt of consolidated VIEs of $240 million and $259 million at June 30, 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 $1,282 million and $1,377 million at June 30, 2016 and December 31, 2015, respectively

[3] Does not include expense associated with non-qualified community development investments. See Note 8, "Certain Transfers of Financial Assets and Variable Interest Entities," for additional information.