Investments and Restricted Cash and Cash Equivalents and Investments - EGTS - Reconciliation of Cash (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	$ 2,047	$ 1,591
Restricted cash and cash equivalents, current	283	173
Restricted cash, cash equivalents and investments, noncurrent	53	53
Total cash and cash equivalents and restricted cash and cash equivalents	2,383	1,817	$ 2,058	$ 1,244
EGTS
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents	12	16
Total cash and cash equivalents and restricted cash and cash equivalents	$ 41	$ 45	$ 64	$ 26