Fair Value Measurements - Changes in Level 3 Financial Assets and Financial Liabilities Carried at Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Transfers into/(out of) Level 3
Change in unrealized gain or (loss) included in Other comprehensive loss for assets held at the end of the reporting period	$ 3	$ (60)
Debt and Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	447
Beginning balance, including held for sale assets		796
(Losses) gains included in Shareholders' net income	(2)	11
Gains (losses) included in Other comprehensive loss	8	(59)
Purchases, sales and settlements
Purchases	10	158
Settlements	(52)	(207)
Total purchases, sales and settlements	(42)	(49)
Transfers into/(out of) Level 3
Transfers into Level 3	95	124
Transfers out of Level 3	(59)	(376)
Total transfers into/(out of) Level 3	36	(252)
Ending balance		447
Ending balance, including held for sale assets	447
Total losses included in Shareholders' net income attributable to instruments held at the reporting date	$ (2)	$ (2)

This element represents total gains or losses for the period (realized and unrealized), arising from assets included in income attributable to instruments held at the reporting date, measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in asset value.

No definition available.