Fair Value Measurement - Schedule of Earnings Related to Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets:
Loans held for investment	$ (230)	$ (80)	$ (24)
Loans held for sale	(2)	(1)	0
Other assets	(19)	(45)	(12)
Total	$ (251)	$ (126)	$ (36)