Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unrealized gains (losses) on cash flow hedging instruments:
Balance at beginning of period		$ (15)	$ (52)	$ (97)
Net gains arising during period, net of tax		11	29	38
Reclassification adjustment for losses realized in net income, net of tax	[1]	4	8	7
Total other comprehensive income for period		15	37	45
Balance at end of period		0	(15)	(52)
Net gains arising during period, taxes		6	16	20
Reclassification adjustment for losses realized in net income, taxes		3	5	4
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent		(1)	26	4
Pension and postretirement benefit plan liability:
Balance at beginning of period		29	(13)	(11)
Change in unfunded pension and postretirement liability, net of tax of $(1) million, $26 million and $(4) million, respectively		(1)	43	(3)
Reclassification adjustment for losses realized in net income, net of tax	[2]	(4)	(1)	1
Pension and postretirement benefit plan adjustments		(5)	42	(2)
Balance at end of period		24	29	(13)
Reclassification adjustment for losses realized in net income, tax		(1)	(1)	2
Total accumulated other comprehensive income (loss) at end of period		$ 24	$ 14	$ (65)

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

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