Stockholders' Equity - Narrative (Detail) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	May 31, 2020	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Oct. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in public offering of common stock (in shares)	2,587,500
Issuance of common stock in public offering of common stock	$ 1,700,000,000
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, approved (in shares)			689,992
Weighted-average grant date fair value (in dollars per share)			$ 661.05
Service period (in years)			3 years 7 months 2 days
2020 ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of stock, equity offering agreement, authorized					$ 1,500,000,000
Issuance of common stock in public offering of common stock (in shares)			137,604
Issuance of common stock in public offering of common stock			$ 99,600,000
Sale of stock, equity offering agreement, available for sale			$ 1,400,000,000
Legacy ATM Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock in public offering of common stock (in shares)		0		162,530
Issuance of common stock in public offering of common stock				$ 101,800,000