Nonperforming Assets (Detail) - USD ($) $ in Millions		Mar. 31, 2018		Dec. 31, 2017
Financing Receivable, Recorded Investment, Nonaccrual Status	[2]	$ 712	[1]	$ 674	[3]
OREO		59		57
Other repossessed assets		7		10
Total nonperforming assets		778		741
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		216	[1]	215	[3]
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		46	[1]	24	[3]
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		0	[1]	1	[3]
Residential Nonguaranteed [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		253	[1],[4]	206	[3],[5]
Home Equity Line of Credit [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		169	[1]	203	[3]
Residential Construction [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		16	[1]	11	[3]
Consumer Other Direct [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		8	[1]	7	[3]
Consumer Indirect [Member]
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 4	[1]	$ 7	[3]

[1] Nonaccruing loans past due 90 days or more totaled $417 million. Nonaccruing loans past due fewer than 90 days include nonaccrual loans modified in TDRs, performing second lien loans where the first lien loan is nonperforming, and certain energy-related commercial loans.

[2] Nonaccruing restructured loans are included in total nonaccrual loans/NPLs.

[3] Nonaccruing loans past due 90 days or more totaled $357 million. Nonaccruing loans past due fewer than 90 days include nonaccrual loans modified in TDRs, performing second lien loans where the first lien loan is nonperforming, and certain energy-related commercial loans.

[4] Includes $188 million of loans measured at fair value, the majority of which were accruing current.

[5] Includes $196 million of loans measured at fair value, the majority of which were accruing current.