Real Estate - 2022 Real Estate Investment Acquisitions (Details) $ in Millions	1 Months Ended				12 Months Ended
	Jan. 31, 2023 USD ($)	May 31, 2022 USD ($) property	Mar. 31, 2022 USD ($) property	Jan. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) property
Medical Office
Real Estate [Line Items]
Number of properties acquired | property						2
Massachusetts | Life Science
Real Estate [Line Items]
Payments to acquire real estate | $				$ 72	$ 18	$ 498
Number of properties acquired | property						8
Massachusetts | Life Science | Subsequent Event
Real Estate [Line Items]
Payments to acquire real estate | $	$ 9
Massachusetts | Medical Office
Real Estate [Line Items]
Payments to acquire real estate | $						$ 55
Number of properties acquired | property						1
California | Life Science
Real Estate [Line Items]
Payments to acquire real estate | $				$ 24		$ 20
Number of properties acquired | property						1
Texas | Medical Office
Real Estate [Line Items]
Payments to acquire real estate | $			$ 43			$ 60
Number of properties acquired | property			2			2
ARKANSAS | Medical Office
Real Estate [Line Items]
Payments to acquire real estate | $		$ 26
Number of properties acquired | property		1