Stockholders' Equity of the Company - Stock Repurchase Program (Details)	3 Months Ended				12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares	Sep. 30, 2018 $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Mar. 31, 2018 $ / shares shares	Dec. 31, 2018 USD ($) increase	Dec. 31, 2017 USD ($) $ / shares shares	Aug. 31, 2016 USD ($)
Class of Stock [Line Items]
Number of shares purchased (in shares) | shares	2,358,484	252,947	3,479,552	3,653,928		8,342,411
Maximum approximate dollar value of shares that may yet be purchased under the plan | $ / shares	$ 93.04	$ 99.75	$ 97.22	$ 97.07		$ 101.64
2016 Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount | $	$ 500,000,000		$ 500,000,000		$ 500,000,000	$ 500,000,000	$ 1,000,000,000.0
Number of increases to share repurchase program | increase					3
Stock repurchase program, authorized amount, total | $	$ 2,500,000,000.0				$ 2,500,000,000.0
Number of shares purchased (in shares) | shares	18,087,322	15,728,838	15,475,891	11,996,339		8,342,411