Nonperforming Assets (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017		Dec. 31, 2016
Document Period End Date		Mar. 31, 2017
Nonaccruing	[2]	$ 789	[1]	$ 845	[3]
OREO	[4]	62		60
Other repossessed assets		7		14
Total nonperforming assets		858		919
Commercial and Industrial [Member]
Nonaccruing		328		390
Commercial Real Estate [Member]
Nonaccruing		6		7
Commercial Construction [Member]
Nonaccruing		18		17
Residential Nonguaranteed [Member]
Nonaccruing		179		177
Home Equity Line of Credit [Member]
Nonaccruing		237		235
Residential Construction [Member]
Nonaccruing		12		12
Consumer Other Direct [Member]
Nonaccruing		5		6
Consumer Indirect [Member]
Nonaccruing		$ 4		$ 1

[1] Nonaccruing loans past due 90 days or more totaled $348 million. Nonaccruing loans past due fewer than 90 days include modified nonaccrual loans reported as 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/NPLs.

[3] Nonaccruing loans past due 90 days or more totaled $360 million. Nonaccruing loans past due fewer than 90 days include modified nonaccrual loans reported as TDRs and performing second lien loans where the first lien loan is nonperforming, and certain energy-related commercial loans.

[4] Does not include foreclosed real estate related to loans insured by the FHA or guaranteed by the VA. Proceeds due from the FHA and the VA are recorded as a receivable in other assets in the Consolidated Balance Sheets until the property is conveyed and the funds are received. The receivable related to proceeds due from the FHA or the VA totaled $50 million at both March 31, 2017 and December 31, 2016.