Fair Value Measurements - Debt Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2023
Debt Instrument [Line Items]
Notes payable, fair value	$ 5,471,700	$ 5,437,200
Current portion of notes payable	1,749,100	1,748,600
Notes payable	6,297,800	6,295,800
Senior Notes
Debt Instrument [Line Items]
Notes payable, current, fair value disclosure	1,746,100	1,741,000
Current portion of notes payable	1,749,100	1,748,600
4.050% Senior Notes due 2025 | Senior Notes
Debt Instrument [Line Items]
Notes payable, current, fair value disclosure	1,746,100	1,741,000
Current portion of notes payable	1,749,100	1,748,600
2.25% Senior Notes due May 1, 2030
Debt Instrument [Line Items]
Notes payable, fair value		1,295,600
2.25% Senior Notes due May 1, 2030 | Senior Notes
Debt Instrument [Line Items]
Notes payable, fair value	1,323,300
Notes payable	1,495,000	1,494,700
5.200% Senior Notes due 2045
Debt Instrument [Line Items]
Notes payable, fair value		1,008,000
5.200% Senior Notes due 2045 | Senior Notes
Debt Instrument [Line Items]
Notes payable, fair value	1,008,200
Notes payable	1,101,200	1,101,100
3.250% Senior Notes, Due February 15, 2051
Debt Instrument [Line Items]
Notes payable, fair value		448,900
3.250% Senior Notes, Due February 15, 2051 | Senior Notes
Debt Instrument [Line Items]
Notes payable, fair value	448,700
Notes payable	477,400	476,400
3.150% Senior Notes due May 1, 2050
Debt Instrument [Line Items]
Notes payable, fair value		943,700
3.150% Senior Notes due May 1, 2050 | Senior Notes
Debt Instrument [Line Items]
Notes payable, fair value	945,400
Notes payable	1,475,100	1,475,000
Non-Current Portion Of Notes Payable And Term Loan | Senior Notes
Debt Instrument [Line Items]
Notes payable, fair value	3,725,600	3,696,200
Notes payable	$ 4,548,700	$ 4,547,200
The Credit Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 1,500,000
The Credit Facility | Line of Credit | Reata Pharmaceuticals, Inc | Secured Debt
Debt Instrument [Line Items]
Long-term debt, gross			1,000,000
Credit Facility Floating Rate 364-Day Tranche | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			500,000
The Credit Facility Floating Rate Three-Year Tranche | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 500,000