Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			1 Months Ended	3 Months Ended
	Jan. 29, 2024	Jun. 27, 2023	Aug. 31, 2023	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2024
Class of Stock [Line Items]
Common stock share value				$ 228	$ 5	$ 20
At-the-Market Facility
Class of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares)			0.2
Sale of stock, consideration received on transaction			$ 5
Third Stock Purchase Agreement Amendment
Class of Stock [Line Items]
Contract with customer, asset, before allowance for credit loss							$ 228
Capitalized contract cost, gross							$ 5
Gilead | Second Stock Purchase Agreement
Class of Stock [Line Items]
Common stock shares issued (in shares)		1.0
Shares issued, price per share (in dollars per share)		$ 19.26
Common stock share value		$ 20
Gilead | Third Stock Purchase Agreement Amendment
Class of Stock [Line Items]
Common stock shares issued (in shares)	15.2
Shares issued, price per share (in dollars per share)	$ 21.00
Common stock share value	$ 320
Premiums earned, net	$ 87