Operating Lease Equipment (Additional Information) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	[1]
Operating Lease Equipment
Other Asset Impairment Charges	$ (20)	$ 0
Operating lease equipment | Commercial Banking
Operating Lease Equipment
Other Asset Impairment Charges	$ 31

[1] A net tax deficiency of $ 1 million was reclassified from capital surplus to applicable income tax expense at March 31, 2016, related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effective date of January 1, 2016.