Stock-Based Compensation - General Employees Stock Purchase Plan (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Amounts recognized in the financial statements
Compensation expense	$ 274	$ 263	$ 274
Employee Stock
Amounts recognized in the financial statements
Number of shares authorized (in shares)	60
Option price, percentage of market value at date of grant (as a percent)	85.00%
Weighted-average fair value (in dollars per share)	$ 15.77	$ 21.20	$ 27.80
Option price, discount from market value at date of grant (as a percent)	15.00%
Compensation expense	$ 21	$ 31	$ 32