Certain Transfers of Financial Assets and Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015
Derivative Asset, Notional Amount		$ 143,941			$ 123,257
Cash Flows Between Transferor and Transferee, Receipts on Transferor's Interest in Transferred Financial Assets, Other		3		$ 4
Long-term Debt	[1]	8,514			8,462
Total liabilities		170,105			167,380
Total assets		$ 194,158			190,817
Government Guarantee Percent		2.00%
Trading assets	[2]	$ 7,050			6,119
Other Assets		5,690			5,582
Affordable Housing Tax Credits and Other Tax Benefits, Amount		19		14
Amortization Method Qualified Affordable Housing Project Investments, Amortization		19		14
Amortization of Intangible Assets	[3]	2		1
Amortization		10		7
Other Noninterest Expense		107		111
Potential loss on securitization of loans		729
Affordable Housing Investment [Member]
Properties sold, carrying value		0		63
Affordable Housing [Member]
Gain (Loss) on Sale of Properties				18
Variable Interest Entity, Not Primary Beneficiary [Member] | Community Development Investments [Member]
Amortization of Intangible Assets		9		6
Variable Interest Entity, Primary Beneficiary [Member]
Long-term Debt		250			259
Residential Mortgage [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Loans and Leases Receivable, Gain (Loss) on Sales, Net		69		$ 77
Transferor's Interests in Transferred Financial Assets, Fair Value		36			38
Total assets		235			241
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total liabilities		434			482
Total assets		475			525
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Preference Shares [Member]
Total assets		3			2
Commercial and Corporate Loans [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Senior Subordinated Notes [Member]
Total assets		7			8
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Long-term Debt		250			259
Loans Receivable, Net		$ 252			262
Student Loans [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Maximum [Member]
Government Guarantee Percent		100.00%
Total Return Swap [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Derivative Asset, Notional Amount		$ 2,200			2,200
Trading assets		2,300			2,200
Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Total assets		1,700			1,600
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		401			321
Real Estate Variable Interest Entity Borrowings		135			132
Limited Partner [Member] | Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Other Assets		738			672
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount		1,076			1,064
Loans issued by the Company to the limited partnerships		$ 238			$ 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
Proceeds from Securitizations of Consumer Loans			$ 1,000

[1] Includes debt of consolidated VIEs of $250 million and $259 million at March 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 $1,484 million and $1,377 million at March 31, 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.