Debt - Summary of Issuances and Redemptions of Senior Notes (Detail) € in Thousands, £ in Thousands, $ in Thousands	1 Months Ended	6 Months Ended
	Jan. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2020 EUR (€)	Jun. 30, 2020 GBP (£)	Jan. 31, 2020 EUR (€)
February 2022 – 2035 Senior Notes [Member] | EUR
Debt Instrument [Line Items]
Aggregate Principal		$ 1,485,405	€ 1,350,000
Maturity Dates		2022-02
Maturity Dates		2035-02
February 2022 – 2035 Senior Notes [Member] | EUR | Weighted Average [Member]
Debt Instrument [Line Items]
Stated Interest Rate		0.60%	0.60%	0.60%
April 2027 – 2050 Senior Notes [Member] | USD
Debt Instrument [Line Items]
Aggregate Principal		$ 2,200,000
Maturity Dates		2027-04
Maturity Dates		2050-04
April 2027 – 2050 Senior Notes [Member] | USD | Weighted Average [Member]
Debt Instrument [Line Items]
Stated Interest Rate		2.40%	2.40%	2.40%
February 2035 Senior Notes [Member] | GBP
Debt Instrument [Line Items]
Aggregate Principal		$ 322,490		£ 250,000
Maturity Dates		2035-02
February 2035 Senior Notes [Member] | GBP | Weighted Average [Member]
Debt Instrument [Line Items]
Stated Interest Rate		1.90%	1.90%	1.90%
June 2027 – 2050 Senior Notes [Member] | JPY
Debt Instrument [Line Items]
Aggregate Principal		$ 386,314		£ 41,200,000
Maturity Dates		2027-06
Maturity Dates		2050-06
June 2027 – 2050 Senior Notes [Member] | JPY | Weighted Average [Member]
Debt Instrument [Line Items]
Stated Interest Rate		1.00%	1.00%	1.00%
January 2020 Senior Notes [Member] | EUR
Debt Instrument [Line Items]
Aggregate Principal	$ 445,880				€ 400,000
Maturity Dates	2020-01
January 2020 Senior Notes [Member] | EUR | Euribor [Member]
Debt Instrument [Line Items]
Stated Interest Rate	0.00%				0.00%
May 2021 Senior Notes [Member] | EUR
Debt Instrument [Line Items]
Stated Interest Rate		1.40%	1.40%	1.40%
Aggregate Principal		$ 783,090	€ 700,000
Maturity Dates		2021-05
January 2022 Senior Notes [Member] | EUR
Debt Instrument [Line Items]
Stated Interest Rate		3.00%	3.00%	3.00%
Aggregate Principal		$ 238,067	€ 212,598
Maturity Dates		2022-01
February 2024 Senior Notes [Member] | EUR
Debt Instrument [Line Items]
Stated Interest Rate		3.40%	3.40%	3.40%
Aggregate Principal		$ 112,524	€ 100,486
Maturity Dates		2024-02