Debt - Summary of Debt (Parenthetical) (Detail) $ in Thousands, £ in Millions		Dec. 31, 2020 USD ($)		Dec. 31, 2020 GBP (£)		Dec. 04, 2020	Dec. 31, 2019 USD ($)		Jul. 26, 2019	Sep. 07, 2017	Mar. 24, 2017	Jul. 22, 2016	Feb. 22, 2016	Aug. 19, 2015	Apr. 17, 2014
Debt Instrument [Line Items]
Debt		$ 8,934,187					$ 7,089,520
GBP-denominated Borrowings [Member]
Debt Instrument [Line Items]
Debt | £				£ 121
4.000% Senior Unsecured Notes Due 2022 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		4.00%	[1]	4.00%	[1]		4.00%	[1]						4.00%
Debt	[1]	$ 610,800					$ 560,650
2.550% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate	[1]	2.55%		2.55%			2.55%
Debt	[1]	$ 546,800					$ 530,280
5.500% Senior Unsecured Notes Due 2024 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		5.50%		5.50%			5.50%								5.50%
Debt							$ 300,000
6.375% Senior Unsecured Notes due 2024 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		6.375%		6.375%			6.375%						6.375%
Debt							$ 500,000
3.325% Senior Unsecured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		3.325%	[1]	3.325%	[1]		3.325%	[1]			3.325%
Debt	[1]	$ 610,800					$ 560,650
5.250% Senior Unsecured Notes Due 2026 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		5.25%		5.25%			5.25%					5.25%
Debt		$ 500,000					$ 500,000
5.000% Senior Unsecured Notes Due 2027 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		5.00%		5.00%			5.00%			5.00%
Debt		$ 1,400,000					$ 1,400,000
3.692% Senior Unsecured Notes due 2028 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate	[1]	3.692%		3.692%			3.692%
Debt	[1]	$ 820,200					$ 795,420
4.625% Senior Unsecured Notes Due 2029 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		4.625%		4.625%			4.625%		4.625%
Debt		$ 900,000					$ 900,000
3.500% Senior Unsecured Notes Due 2031 [Member]
Debt Instrument [Line Items]
Senior unsecured notes, interest rate		3.50%		3.50%		3.50%	3.50%
Debt		$ 1,300,000

[1] Non-U.S. dollar denominated debt that reflects the exchange rate at period end.