Credit Quality (Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment) (Parenthetical) (Detail) $ in Millions	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2016 USD ($)		Jun. 30, 2015 USD ($)		Jun. 30, 2016 USD ($) number		Jun. 30, 2015 USD ($)		Dec. 31, 2015 USD ($) number		Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Financing Receivable, Allowance for Credit Losses
Allowance for loan and lease losses	$ 1,299	[1],[2]	$ 1,293		$ 1,299	[1],[2]	$ 1,293		$ 1,272	[1],[3]	$ 1,295	$ 1,300	$ 1,322
Portfolio loans and leases	$ 93,755	[4],[5]			$ 93,755	[4],[5]			92,415	[6]
Number of contracts	2,669	[7],[8]	3,468	[9],[10]	5,679	[7],[8]	7,676	[9],[10]
Recorded investment	$ 2,032	[11]			$ 2,032	[11]			1,842	[12]
Variable Interest Entity, Primary Beneficiary
Financing Receivable, Allowance for Credit Losses
Allowance for loan and lease losses	28				28				28
Commercial | Variable Interest Entity, Primary Beneficiary
Financing Receivable, Allowance for Credit Losses
Allowance for loan and lease losses	18				$ 18				$ 15
Number of contracts | number					5				5
Recorded investment	27				$ 27				$ 27
Leveraged Leases
Financing Receivable, Allowance for Credit Losses
Allowance for loan and lease losses	3				3				5
Portfolio loans and leases	818				818				801
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses
Portfolio loans and leases at fair value	$ 154				$ 154				$ 167

[1] Includes $ 128 and $ 152 of cash and due from banks, $ 1,853 and $ 2,537 of portfolio loans and leases , $ (28) and $ (28) of ALLL, $ 11 and $ 14 of other assets, $ 3 and $ 3 of other liabilities , and $ 1,744 and $ 2,487 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2016 and December 31, 2015 , respectively. For further information refer to Note 9 .

[2] Includes $ 3 related to leveraged leases at June 30, 2016 .

[3] Includes $ 5 related to leveraged leases at December 31, 2015 .

[4] Excludes $ 154 of residential mortgage loans measured at fair value at June 30, 2016 .

[5] Excludes $ 154 of residential mortgage loans measured at fair value, and includes $ 818 of leveraged leases, net of unearned income at June 30, 2016 .

[6] Excludes $ 167 of residential mortgage loans measured at fair value, and includes $ 801 of leveraged leases, net of unearned income at December 31, 2015 .

[7] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[8] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[9] Excludes all loans and leases held for sale and loans acquired with deteriorated credit quality which were accounted for within a pool .

[10] Represents number of loans post-modification and excludes loans previously modified in a TDR .

[11] Includes $ 431 , $ 633 and $ 349 , respectively, of commercial, residential mortgage and consumer portfolio TDRs on accrual status and $ 242 , $ 16 an d $ 50 , respectively , of commercial , residential mortgage and consumer portfolio TDRs on nonaccrual status at June 30, 2016 .

[12] Includes $ 491 , $ 607 and $ 372 , respectively, of commercial , resid ential mortgage and consumer portfolio TDR s on accrual status and $ 2 03 , $ 2 3 and $ 52 , respectively , of commercial, reside ntial mortgage and consumer portfolio TDR s on nonaccrual status at December 31, 2015 .