Share-Based Compensation - Summary of Outstanding and Exercisable Options and SARs (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of SARs outstanding
Fair value of SARs vested	$ 3,000,000	$ 8,000,000	$ 9,000,000
Income tax benefit	$ 9,000,000	11,000,000	7,000,000
Vesting period for SARs (years)	2 years 3 months 25 days
Stock Option
Summary of SARs outstanding
Aggregate intrinsic value, Outstanding		4,000,000
Aggregate intrinsic value, Exercisable		$ 4,000,000
Weighted-average remaining contractual term, Outstanding		1 year 3 months 25 days
Weighted-average remaining contractual term, Exercisable		1 year 3 months 25 days
Intrinsic value of SARs exercised	$ 2,000,000	$ 10,000,000	15,000,000
Stock Appreciation Rights (SARs)
Summary of SARs outstanding
Aggregate intrinsic value, Outstanding	28,000,000
Aggregate intrinsic value, Exercisable	$ 20,000,000
Weighted-average remaining contractual term, Outstanding	7 years
Weighted-average remaining contractual term, Exercisable	5 years
Intrinsic value of SARs exercised	$ 6,000,000	11,000,000	$ 11,000,000
Cash received from the exercise of SARs	6,000,000	7,000,000
Income tax benefit	1,000,000	3,000,000
Employee Stock Option
Summary of SARs outstanding
Cash received from the exercise of SARs	2,000,000	9,000,000
Income tax benefit	$ 1,000,000	$ 2,000,000
Maximum
Summary of SARs outstanding
Vesting period for SARs (years)	4 years