Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Unrealized Gains (Losses) on Fair Value Option Debt Attributable to Credit [Abstract]
Balance at beginning of period		$ (24,000,000)	$ 0	$ (19,000,000)	$ 0
Cumulative effect adjustment to initially apply new accounting guidance for fair value option debt attributable to credit, net of tax	[1]					$ (19,000,000)
Net (loss) arising during period, net of tax				(5,000,000)	0
Total other comprehensive loss for period				(5,000,000)	0
Balance at end of period		(24,000,000)	0	(24,000,000)	0
Cumulative effect adjustment to initially apply new accounting guidance for fair value option debt attributable to credit, tax				(11,000,000)	0
Net (loss) arising during period, tax		0	0	(3,000,000)	0
Unrealized gains (losses) on cash flow hedging instruments:
Balance at beginning of period		0	(7,000,000)	0	(15,000,000)
Net gains arising during period, net of tax		0	4,000,000	0	11,000,000
Reclassification adjustment for losses realized in net income, net of tax	[2]	0	3,000,000	0	4,000,000
Total other comprehensive income for period		0	7,000,000	0	15,000,000
Balance at end of period		0	0	0	0
Net gains arising during period, taxes		0	2,000,000	0	6,000,000
Reclassification adjustment for losses realized in net income, taxes		0	(1,000,000)	0	3,000,000
Pension and postretirement benefit plan liability:
Balance at beginning of period		23,000,000	28,000,000	24,000,000	29,000,000
Reclassification adjustment for (gains) losses realized in net income, net of tax	[3]	(9,000,000)	(2,000,000)	(10,000,000)	(3,000,000)
Total other comprehensive income for period		(9,000,000)	(2,000,000)	(10,000,000)	(3,000,000)
Balance at end of period		14,000,000	26,000,000	14,000,000	26,000,000
Reclassification adjustment for losses realized in net income, tax		(5,000,000)	0	(6,000,000)	(1,000,000)
Total accumulated other comprehensive income (loss) at end of period		$ (10,000,000)	$ 26,000,000	(10,000,000)	26,000,000	$ 24,000,000
As Previously Reported [Member]
Unrealized Gains (Losses) on Fair Value Option Debt Attributable to Credit [Abstract]
Balance at beginning of period				$ 0	$ 0

[1] For information on the adoption of new accounting guidance related to fair value option debt attributable to our credit spreads, see Note 13, "New Accounting Pronouncements."

[2] The amounts reclassified relate to currency swaps and are included as a component of interest expense in our consolidated statement of income (loss).

[3] The amounts reclassified are included as a component of salaries and employee benefits in our consolidated statement of income (loss).