Stockholders' Equity (Detail)					12 Months Ended				47 Months Ended
	Feb. 20, 2020 shares	Dec. 18, 2019 USD ($) shares	Jan. 29, 2019 shares	Dec. 14, 2018 USD ($) shares	Dec. 31, 2020 USD ($) transactions shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares		Dec. 31, 2019 USD ($) shares	Oct. 22, 2020 USD ($)
Class of Stock [Line Items]
Shares acquired (in shares) | shares	175,340	1,431,989	117,751	1,057,035
Repurchase of common stock					$ 849,909,000	$ 694,909,000	$ 958,696,000
Shares acquired					3,448,402,000	2,523,493,000			$ 2,523,493,000
Repurchase of common stock					$ 849,910,000	$ 694,909,000	$ 958,696,000	[1]
Number of transactions | transactions					2
Repurchase agreements
Class of Stock [Line Items]
Shares acquired (in shares) | shares									14,616,942
Repurchase of common stock									$ 3,100,000,000
Repurchase of common stock		$ 500,000,000		$ 220,000,000
Common Stock
Class of Stock [Line Items]
Increase in authorized amount of repurchases										$ 1,000,000,000.0
Aggregate authorized repurchase amount										$ 4,100,000,000
Shares acquired (in shares) | shares					3,497,285	2,211,866	4,793,687
Remaining authorized repurchase amount					$ 1,000,000,000.0
Shares acquired					$ 940,800,000	$ 636,800,000	$ 925,700,000		$ 636,800,000
Common Stock | Repurchase agreements
Class of Stock [Line Items]
Aggregate authorized repurchase amount		$ 500,000,000		$ 220,000,000

[1] The Company applied the modified retrospective transition method when adopting ASU 2016-02 "Leases", therefore the Company's 2018 prior results were not restated to reflect ASU 2016-02. Refer to footnote 14.