Stockholders' Equity of the Company - Additional Information (Details)	1 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2019 $ / shares shares	Mar. 31, 2019 $ / shares shares	Sep. 30, 2019 USD ($) increase $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)	Aug. 31, 2016 USD ($)
Equity, Class of Treasury Stock [Line Items]
Authorized capital stock (shares)	260,000,000	260,000,000			260,000,000
Authorized shares, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01			$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000			160,000,000	160,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01			$ 0.01	$ 0.01
Excess stock, shares authorized (shares)	75,000,000	75,000,000			75,000,000
Excess stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01			$ 0.01
Preferred stock, shares authorized (shares)	25,000,000	25,000,000			25,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01			$ 0.01
Excess shares issued (shares)	0	0			0
Shares repurchased	108,300	916,439	866,924	397,783		9,744,911	8,342,411
Average price paid per share (in dollars per share) | $ / shares		$ 81.31	$ 86.58	$ 86.07		$ 96.22	$ 101.64
2016 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount | $						$ 500,000,000.0	$ 500,000,000	$ 500,000,000	$ 1,000,000,000.0
Number of increases to share repurchase program | increase					3
Shares repurchased		20,268,468	19,352,029	18,485,105		18,087,322	8,342,411
Stock repurchase program, authorized amount | $	$ 2,500,000,000	$ 2,500,000,000			$ 2,500,000,000