Summary of Significant Accounting Policies - PAC - Reconciliation of Cash (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 1,591	$ 1,096
Investments and restricted cash and cash equivalents	173	127
Investments and restricted cash and cash equivalents and investments	53	21
Total cash and cash equivalents and restricted cash and cash equivalents	1,817	1,244	$ 1,445	$ 1,268
PAC
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	641	179
Investments and restricted cash and cash equivalents	7	4
Investments and restricted cash and cash equivalents and investments	26	3
Total cash and cash equivalents and restricted cash and cash equivalents	$ 674	$ 186	$ 19	$ 36