Stockholders' Equity - Summary of Changes in Common Stock and Common Stock in Treasury (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares, beginning of year	227,638,738	225,625,636	224,683,653
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	480,283	481,834	419,844
Forfeited or expired (in shares)	(184,235)	(89,699)	(185,056)
Shares issued for vested restricted stock units	607,231	179,826	172,071
Number of shares issued, end of year	230,080,944	227,638,738	225,625,636
Number of shares held, beginning of year	34,156,355	29,612,337	14,151,759
Number of shares held, end of year	61,485,423	34,156,355	29,612,337
Number of common stock outstanding, end of year	168,595,521	193,482,383	196,013,299
Common Stock in Treasury
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Repurchase of common stock (in shares)	27,320,816	4,680,313	16,123,111
Profit sharing contribution paid in stock (in shares)	(502,519)	(830,613)	(787,463)
Restricted stock shares forfeitures transferred to Omnibus Incentive Plan Reserve	0	0	(75,638)
Restricted stock shares, forfeited	0	(1,813)	0
Shares withheld for taxes	510,771	696,131	200,568
2002 Directors Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Shares granted and issued under the Omnibus Incentive Plan and Directors Stock Plan to Directors	15,768	21,537	20,246
2012 President and COO Four-year Incentive Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	0	325,000	0
2014 Special PSU Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	749,653	0	0
Number of units granted (in shares)	641,480
2014 Three-year PSU Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	636,723	0	0
2013 Three-year PSU Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	0	1,074,017	0
2012 Three-year PSU Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock shares issued for new awards under the Omnibus Incentive Plan and 2005 Contingent Stock Plan	0	0	442,985
SLO Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of units granted (in shares)	136,783	20,587	71,893