Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gains (losses)		$ (5)	$ (12)	$ 19
Net actuarial loss amortization of net actuarial losses		3
Actuarial loss expected to be recognized in net periodic pension cost, net of tax		2
Unfunded status		$ (6)
Approximate time period considered for investment performance to determine expected return on plan assets (in years)		ten-year
Expected contribution to plans		$ 12
Minimum age for participation of employees in 401(k)plan		21 years
Contribution by each participant of defined contribution plans on a pretax basis to the plan subject to certain maximum limits		Each participant may contribute on a pretax basis between 1% and 50% of his or her eligible compensation to the plan subject to certain maximum limits.
Eligible employees enrollment		After 90 days
Minimum period of service for provide matching contribution to employee		1 year
Defined contribution plan, cost recognized		$ 16	16	16
Balance of publicly traded common stock defined contribution plan		$ 72	82
Collective bargaining agreement expiration date		Jun. 30, 2026
Maximum contributions by employer		less than 5%
Health care contributions		$ 26	$ 24	$ 24
Debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation securities		28.00%
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation securities		28.00%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation securities		44.00%
Assumptions [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed annual rate of increase in the per capita cost of covered health care benefits		7.00%
Assumed ultimate annual rate decrease of per capita cost of covered health		5.00%
Effect of one-percentage point change in assumed health care cost trend rates on postretirement benefit obligation		$ 1
Other liabilities [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded status		43
Accrued expenses [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded status		3
Other assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded status		$ 40
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial loss expected to be recognized in net periodic pension cost	$ 2