Stockholders' Equity of the Company - Additional Information (Details)	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) increase $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Aug. 31, 2016 USD ($)
Equity, Class of Treasury Stock [Line Items]
Authorized capital stock (shares)	260,000,000			260,000,000
Authorized shares, par value (in dollars per share) | $ / shares	$ 0.01			$ 0.01
Common stock, shares authorized (in shares)	160,000,000			160,000,000	160,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.01			$ 0.01	$ 0.01
Excess stock, shares authorized (shares)	75,000,000			75,000,000
Excess stock, par value (in dollars per share) | $ / shares	$ 0.01			$ 0.01
Preferred stock, shares authorized (shares)	25,000,000			25,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01			$ 0.01
Excess shares issued (shares)	0			0
Shares repurchased	252,947	3,479,552	3,653,928		8,342,411
Average price paid per share (in dollars per share) | $ / shares	$ 99.75	$ 97.22	$ 97.07		$ 101.64
2016 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount | $		$ 500,000,000			$ 500,000,000	$ 1,000,000,000.0
Number of increases to share repurchase program | increase				2
Shares repurchased	15,728,838	15,475,891	11,996,339		8,342,411
Maximum approximate dollar value of shares that may yet be purchased under the plan | $	$ 433,600,000	$ 458,900,000	$ 797,200,000	$ 433,600,000	$ 1,152,000,000
Stock repurchase program, authorized amount | $	$ 2,000,000,000.0			$ 2,000,000,000.0