Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Uncertainties [Abstract]
Balance at January 1	$ 1,515	$ 1,458	$ 1,225
Additions for tax positions related to the current year	89	106	110
Additions for tax positions of prior years	5	23	282
Reductions for tax positions of prior years	(141)	(56)	(49)
Settlements	(26)	(16)	(110)
Balance at December 31	1,442	1,515	1,458
Gross interest expense related to unrecognized tax benefits	62	34	39
Total accrued interest balance at December 31	$ 233	$ 190	$ 165