Real Estate - 2021 Real Estate Investment Acquisitions (Details) $ in Millions	1 Months Ended			12 Months Ended
	Jan. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jan. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) a property	Dec. 31, 2023 USD ($)	Apr. 30, 2021 USD ($)
Lab | MASSACHUSETTS
Real Estate [Line Items]
Number of properties acquired | property				8
Payments to acquire real estate	$ 9	$ 18	$ 72	$ 498
Lab | CALIFORNIA
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate			$ 24	$ 20
Lab | CALIFORNIA | South San Francisco, California
Real Estate [Line Items]
Payments to acquire real estate				$ 128
Area of land | a				12
Outpatient Medical | Mortgage Debt
Real Estate [Line Items]
Face amount					$ 142	$ 142
Outpatient Medical | MASSACHUSETTS
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 55
Outpatient Medical | TENNESSEE
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 13
Outpatient Medical | COLORADO
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 38
Outpatient Medical | UNITED STATES
Real Estate [Line Items]
Number of properties acquired | property				14
Payments to acquire real estate				$ 371
Outpatient Medical | FLORIDA
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 16
Outpatient Medical | KANSAS
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 50
Outpatient Medical | NEW JERSEY
Real Estate [Line Items]
Number of properties acquired | property				3
Payments to acquire real estate				$ 155
Outpatient Medical | TEXAS
Real Estate [Line Items]
Number of properties acquired | property				2
Payments to acquire real estate				$ 60
Outpatient Medical | WASHINGTON
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 43
Outpatient Medical | LOUISIANA
Real Estate [Line Items]
Number of properties acquired | property				1
Payments to acquire real estate				$ 34