Income Taxes - Components of income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current expense (benefit):
United States	$ 251	$ 195	$ 284
Non-U.S.	37	6	11
Current Income Tax Expense (Benefit)	288	201	295
Deferred expense (benefit):
United States	(20)	(96)	(123)
Non-U.S.	(1,141)	(25)	(44)
Deferred Income Tax Expense (Benefit)	(1,161)	(121)	(167)
Income tax expense (benefit)	$ (873)	$ 80	$ 128